<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with Wdesk from Workiva-->
<!--Copyright 2022 Workiva-->
<!--r:6024d6e0-73e0-428e-98bf-3243c1ec9bba,g:7388fe7d-c1de-4567-bdad-47efe0cb0502-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:roleRef roleURI="http://www.paalp.com/role/CONSOLIDATEDBALANCESHEETS" xlink:type="simple" xlink:href="paa-20211231.xsd#CONSOLIDATEDBALANCESHEETS"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/CONSOLIDATEDBALANCESHEETS" xlink:type="extended" id="i462203c6be3f497a8b4bbb6dd425fa44_CONSOLIDATEDBALANCESHEETS">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_91c68177-4481-478f-a6a7-81aedce1892b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract_2d618364-db9b-4dc9-88c4-ec97e95de5af" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_91c68177-4481-478f-a6a7-81aedce1892b" xlink:to="loc_us-gaap_AssetsAbstract_2d618364-db9b-4dc9-88c4-ec97e95de5af" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrentAbstract_07aeee39-07cd-42a2-a0a4-38c827fbd240" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetsCurrentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_2d618364-db9b-4dc9-88c4-ec97e95de5af" xlink:to="loc_us-gaap_AssetsCurrentAbstract_07aeee39-07cd-42a2-a0a4-38c827fbd240" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_58653143-3f23-494e-9cf1-284a9230ce53" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_07aeee39-07cd-42a2-a0a4-38c827fbd240" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_58653143-3f23-494e-9cf1-284a9230ce53" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashCurrent_ce063ba6-269e-44a3-b34e-50fc4aa4c24f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RestrictedCashCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_07aeee39-07cd-42a2-a0a4-38c827fbd240" xlink:to="loc_us-gaap_RestrictedCashCurrent_ce063ba6-269e-44a3-b34e-50fc4aa4c24f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivablesNetCurrent_27c9615e-1efa-432e-8b63-782911b616b1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReceivablesNetCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_07aeee39-07cd-42a2-a0a4-38c827fbd240" xlink:to="loc_us-gaap_ReceivablesNetCurrent_27c9615e-1efa-432e-8b63-782911b616b1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryNet_ce490d69-9c4a-4196-a400-74e3ec4883bb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InventoryNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_07aeee39-07cd-42a2-a0a4-38c827fbd240" xlink:to="loc_us-gaap_InventoryNet_ce490d69-9c4a-4196-a400-74e3ec4883bb" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsCurrent_d1b3ce34-7a2f-4f91-9218-4c1ee81a0e2f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherAssetsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_07aeee39-07cd-42a2-a0a4-38c827fbd240" xlink:to="loc_us-gaap_OtherAssetsCurrent_d1b3ce34-7a2f-4f91-9218-4c1ee81a0e2f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrent_23c400ce-ccbf-4e84-b7fb-7c612d7ec8b4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_07aeee39-07cd-42a2-a0a4-38c827fbd240" xlink:to="loc_us-gaap_AssetsCurrent_23c400ce-ccbf-4e84-b7fb-7c612d7ec8b4" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetBeforeAccumulatedDepreciationAndAmortization_7788457e-8097-4e0b-be9b-4fc1b27c97b4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetBeforeAccumulatedDepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_2d618364-db9b-4dc9-88c4-ec97e95de5af" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetBeforeAccumulatedDepreciationAndAmortization_7788457e-8097-4e0b-be9b-4fc1b27c97b4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAccumulatedDepreciationAndAmortization_d04ade90-235a-4246-ae7a-8a46179c2c90" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAccumulatedDepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_2d618364-db9b-4dc9-88c4-ec97e95de5af" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAccumulatedDepreciationAndAmortization_d04ade90-235a-4246-ae7a-8a46179c2c90" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization_6420ec13-621f-4b7b-a4a0-d1bb8f059862" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_2d618364-db9b-4dc9-88c4-ec97e95de5af" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization_6420ec13-621f-4b7b-a4a0-d1bb8f059862" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsNoncurrentAbstract_2f648729-3620-4e03-b3c5-14d25628a949" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherAssetsNoncurrentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_2d618364-db9b-4dc9-88c4-ec97e95de5af" xlink:to="loc_us-gaap_OtherAssetsNoncurrentAbstract_2f648729-3620-4e03-b3c5-14d25628a949" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestments_917f3d7a-ccac-4ea0-abef-543157263678" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherAssetsNoncurrentAbstract_2f648729-3620-4e03-b3c5-14d25628a949" xlink:to="loc_us-gaap_EquityMethodInvestments_917f3d7a-ccac-4ea0-abef-543157263678" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_ab7b6784-c497-41d3-b649-986767ecceb5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherAssetsNoncurrentAbstract_2f648729-3620-4e03-b3c5-14d25628a949" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_ab7b6784-c497-41d3-b649-986767ecceb5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_LinefillAndBaseGas_2d53dc36-58be-4dff-bcf9-2526674d729c" xlink:href="paa-20211231.xsd#paa_LinefillAndBaseGas"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherAssetsNoncurrentAbstract_2f648729-3620-4e03-b3c5-14d25628a949" xlink:to="loc_paa_LinefillAndBaseGas_2d53dc36-58be-4dff-bcf9-2526674d729c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAsset_30550c26-52d8-4970-a266-0a803a79295e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseRightOfUseAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherAssetsNoncurrentAbstract_2f648729-3620-4e03-b3c5-14d25628a949" xlink:to="loc_us-gaap_OperatingLeaseRightOfUseAsset_30550c26-52d8-4970-a266-0a803a79295e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryNoncurrent_eca98b25-b5e7-4483-bdd5-f417f7e7ddd2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InventoryNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherAssetsNoncurrentAbstract_2f648729-3620-4e03-b3c5-14d25628a949" xlink:to="loc_us-gaap_InventoryNoncurrent_eca98b25-b5e7-4483-bdd5-f417f7e7ddd2" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsNoncurrent_97453989-3dbc-4042-b59a-c6659364d5b1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherAssetsNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherAssetsNoncurrentAbstract_2f648729-3620-4e03-b3c5-14d25628a949" xlink:to="loc_us-gaap_OtherAssetsNoncurrent_97453989-3dbc-4042-b59a-c6659364d5b1" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_67ed229d-7fb6-4688-aa4c-a27c29d136d3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Assets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_2d618364-db9b-4dc9-88c4-ec97e95de5af" xlink:to="loc_us-gaap_Assets_67ed229d-7fb6-4688-aa4c-a27c29d136d3" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_86fc273c-5349-495d-b945-12707220cf2c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_91c68177-4481-478f-a6a7-81aedce1892b" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_86fc273c-5349-495d-b945-12707220cf2c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrentAbstract_1753aa3e-0e05-4bc9-9f03-6edf4f4b91ee" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LiabilitiesCurrentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_86fc273c-5349-495d-b945-12707220cf2c" xlink:to="loc_us-gaap_LiabilitiesCurrentAbstract_1753aa3e-0e05-4bc9-9f03-6edf4f4b91ee" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableTradeCurrent_a078edb8-e9a6-4423-88f2-285ec42a5947" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccountsPayableTradeCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_1753aa3e-0e05-4bc9-9f03-6edf4f4b91ee" xlink:to="loc_us-gaap_AccountsPayableTradeCurrent_a078edb8-e9a6-4423-88f2-285ec42a5947" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtCurrent_d467bff4-4c9d-42a7-982f-eecfceeee731" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_1753aa3e-0e05-4bc9-9f03-6edf4f4b91ee" xlink:to="loc_us-gaap_DebtCurrent_d467bff4-4c9d-42a7-982f-eecfceeee731" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesCurrent_1e55ea2c-a4c4-4b20-b9b1-27a3d467fb86" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherLiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_1753aa3e-0e05-4bc9-9f03-6edf4f4b91ee" xlink:to="loc_us-gaap_OtherLiabilitiesCurrent_1e55ea2c-a4c4-4b20-b9b1-27a3d467fb86" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrent_73bf421d-138b-4a53-9e58-cbf64c6a5f3b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_1753aa3e-0e05-4bc9-9f03-6edf4f4b91ee" xlink:to="loc_us-gaap_LiabilitiesCurrent_73bf421d-138b-4a53-9e58-cbf64c6a5f3b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesNoncurrentAbstract_2d5e23ed-2955-401f-abe1-d7e6d0d031c1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LiabilitiesNoncurrentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_86fc273c-5349-495d-b945-12707220cf2c" xlink:to="loc_us-gaap_LiabilitiesNoncurrentAbstract_2d5e23ed-2955-401f-abe1-d7e6d0d031c1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorLongTermNotes_eadb5386-2053-4b06-8426-ed1b37978e52" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SeniorLongTermNotes"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesNoncurrentAbstract_2d5e23ed-2955-401f-abe1-d7e6d0d031c1" xlink:to="loc_us-gaap_SeniorLongTermNotes_eadb5386-2053-4b06-8426-ed1b37978e52" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLongTermDebtNoncurrent_dad6ea20-d815-4263-8bb7-d35c8c241b30" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherLongTermDebtNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesNoncurrentAbstract_2d5e23ed-2955-401f-abe1-d7e6d0d031c1" xlink:to="loc_us-gaap_OtherLongTermDebtNoncurrent_dad6ea20-d815-4263-8bb7-d35c8c241b30" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_c42c4206-aaf3-46d6-a2be-e2c7ebe54126" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseLiabilityNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesNoncurrentAbstract_2d5e23ed-2955-401f-abe1-d7e6d0d031c1" xlink:to="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_c42c4206-aaf3-46d6-a2be-e2c7ebe54126" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesNoncurrent_f06e482f-d3c6-4dfd-ae4f-64a383555415" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherLiabilitiesNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesNoncurrentAbstract_2d5e23ed-2955-401f-abe1-d7e6d0d031c1" xlink:to="loc_us-gaap_OtherLiabilitiesNoncurrent_f06e482f-d3c6-4dfd-ae4f-64a383555415" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesNoncurrent_223b64fd-4727-4597-90c0-bcabce4f3404" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LiabilitiesNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesNoncurrentAbstract_2d5e23ed-2955-401f-abe1-d7e6d0d031c1" xlink:to="loc_us-gaap_LiabilitiesNoncurrent_223b64fd-4727-4597-90c0-bcabce4f3404" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommitmentsAndContingencies_e36e2043-edc0-4c63-bcf0-893d2be4a607" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommitmentsAndContingencies"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_86fc273c-5349-495d-b945-12707220cf2c" xlink:to="loc_us-gaap_CommitmentsAndContingencies_e36e2043-edc0-4c63-bcf0-893d2be4a607" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterestAbstract_3feff4d9-6dfb-4c30-9e0a-b0a215955cb7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterestAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_86fc273c-5349-495d-b945-12707220cf2c" xlink:to="loc_us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterestAbstract_3feff4d9-6dfb-4c30-9e0a-b0a215955cb7" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccount_0d2bbad7-345c-4908-a619-bca9c444c668" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterestAbstract_3feff4d9-6dfb-4c30-9e0a-b0a215955cb7" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccount_0d2bbad7-345c-4908-a619-bca9c444c668" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapital_e7fee1a4-f54e-448c-9d50-34ef7a1d3349" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnersCapital"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterestAbstract_3feff4d9-6dfb-4c30-9e0a-b0a215955cb7" xlink:to="loc_us-gaap_PartnersCapital_e7fee1a4-f54e-448c-9d50-34ef7a1d3349" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapitalAttributableToNoncontrollingInterest_a28c09c2-3f29-4b34-b2b9-454a4c6dcf8b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnersCapitalAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterestAbstract_3feff4d9-6dfb-4c30-9e0a-b0a215955cb7" xlink:to="loc_us-gaap_PartnersCapitalAttributableToNoncontrollingInterest_a28c09c2-3f29-4b34-b2b9-454a4c6dcf8b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest_fffe1f40-826f-42c8-92ad-d169480a7127" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterestAbstract_3feff4d9-6dfb-4c30-9e0a-b0a215955cb7" xlink:to="loc_us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest_fffe1f40-826f-42c8-92ad-d169480a7127" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_d81d7165-8816-4e0b-b923-e16597e01022" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_86fc273c-5349-495d-b945-12707220cf2c" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_d81d7165-8816-4e0b-b923-e16597e01022" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_fdd3d24e-c69d-4ad3-9b64-9c997f51c899" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_91c68177-4481-478f-a6a7-81aedce1892b" xlink:to="loc_us-gaap_StatementTable_fdd3d24e-c69d-4ad3-9b64-9c997f51c899" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_5228c47a-467b-4425-bd49-a6d0e511007a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountByClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_fdd3d24e-c69d-4ad3-9b64-9c997f51c899" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_5228c47a-467b-4425-bd49-a6d0e511007a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_5228c47a-467b-4425-bd49-a6d0e511007a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_5228c47a-467b-4425-bd49-a6d0e511007a" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_5228c47a-467b-4425-bd49-a6d0e511007a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_17a5baad-82f7-4462-b467-f5524c51aff5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_5228c47a-467b-4425-bd49-a6d0e511007a" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_17a5baad-82f7-4462-b467-f5524c51aff5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SeriesAPreferredUnitsMember_c724e290-338c-484c-b3ae-2e3bed0867f7" xlink:href="paa-20211231.xsd#paa_SeriesAPreferredUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_17a5baad-82f7-4462-b467-f5524c51aff5" xlink:to="loc_paa_SeriesAPreferredUnitsMember_c724e290-338c-484c-b3ae-2e3bed0867f7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SeriesBPreferredUnitsMember_66290e4a-ed2b-40a2-90ed-6724de4c934f" xlink:href="paa-20211231.xsd#paa_SeriesBPreferredUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_17a5baad-82f7-4462-b467-f5524c51aff5" xlink:to="loc_paa_SeriesBPreferredUnitsMember_66290e4a-ed2b-40a2-90ed-6724de4c934f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_CommonUnitsMember_e8d49dfe-6f78-4f3d-a7d3-d416c2270420" xlink:href="paa-20211231.xsd#paa_CommonUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_17a5baad-82f7-4462-b467-f5524c51aff5" xlink:to="loc_paa_CommonUnitsMember_e8d49dfe-6f78-4f3d-a7d3-d416c2270420" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/CONSOLIDATEDBALANCESHEETSParenthetical" xlink:type="simple" xlink:href="paa-20211231.xsd#CONSOLIDATEDBALANCESHEETSParenthetical"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/CONSOLIDATEDBALANCESHEETSParenthetical" xlink:type="extended" id="i7494c7edf46d4962a74504d1679a236b_CONSOLIDATEDBALANCESHEETSParenthetical">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_b2647305-1623-481d-8784-be750d0e4cee" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountUnitsOutstanding_0e954fbe-3702-445e-a14e-e99428e5f288" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountUnitsOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_b2647305-1623-481d-8784-be750d0e4cee" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountUnitsOutstanding_0e954fbe-3702-445e-a14e-e99428e5f288" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_4c5db052-5553-492c-972b-f1c4bc5155a7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_b2647305-1623-481d-8784-be750d0e4cee" xlink:to="loc_us-gaap_StatementTable_4c5db052-5553-492c-972b-f1c4bc5155a7" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_9ffd4c2f-7c13-45ed-b101-cdd927efc072" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountByClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_4c5db052-5553-492c-972b-f1c4bc5155a7" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_9ffd4c2f-7c13-45ed-b101-cdd927efc072" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_9ffd4c2f-7c13-45ed-b101-cdd927efc072_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_9ffd4c2f-7c13-45ed-b101-cdd927efc072" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_9ffd4c2f-7c13-45ed-b101-cdd927efc072_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_91b5deeb-d607-4736-8e70-5d8f6fe1bd50" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_9ffd4c2f-7c13-45ed-b101-cdd927efc072" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_91b5deeb-d607-4736-8e70-5d8f6fe1bd50" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SeriesAPreferredUnitsMember_e9f19c0b-ec40-437f-9fdc-89f7ed42cdec" xlink:href="paa-20211231.xsd#paa_SeriesAPreferredUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_91b5deeb-d607-4736-8e70-5d8f6fe1bd50" xlink:to="loc_paa_SeriesAPreferredUnitsMember_e9f19c0b-ec40-437f-9fdc-89f7ed42cdec" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SeriesBPreferredUnitsMember_ed6d9c39-5a88-420f-8add-d7de88d4bfeb" xlink:href="paa-20211231.xsd#paa_SeriesBPreferredUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_91b5deeb-d607-4736-8e70-5d8f6fe1bd50" xlink:to="loc_paa_SeriesBPreferredUnitsMember_ed6d9c39-5a88-420f-8add-d7de88d4bfeb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_CommonUnitsMember_73f21d42-eba8-4ed6-952a-0d4dae2ae304" xlink:href="paa-20211231.xsd#paa_CommonUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_91b5deeb-d607-4736-8e70-5d8f6fe1bd50" xlink:to="loc_paa_CommonUnitsMember_73f21d42-eba8-4ed6-952a-0d4dae2ae304" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/CONSOLIDATEDSTATEMENTSOFOPERATIONS" xlink:type="simple" xlink:href="paa-20211231.xsd#CONSOLIDATEDSTATEMENTSOFOPERATIONS"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/CONSOLIDATEDSTATEMENTSOFOPERATIONS" xlink:type="extended" id="i72a0426a18f048ecb1ea1d7c31b78b8e_CONSOLIDATEDSTATEMENTSOFOPERATIONS">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_44806068-3ae6-4c07-b845-47b17dd9ab89" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenuesAbstract_4ac2e0d5-66a1-4cea-aeb9-9f6d951b40f9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenuesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_44806068-3ae6-4c07-b845-47b17dd9ab89" xlink:to="loc_us-gaap_RevenuesAbstract_4ac2e0d5-66a1-4cea-aeb9-9f6d951b40f9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_3ff63421-87cf-45d8-bab2-edfc54d990f9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_4ac2e0d5-66a1-4cea-aeb9-9f6d951b40f9" xlink:to="loc_us-gaap_Revenues_3ff63421-87cf-45d8-bab2-edfc54d990f9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostsAndExpensesAbstract_d5f6c0e8-1d15-46cd-9db8-3496ed9a74c8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CostsAndExpensesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_44806068-3ae6-4c07-b845-47b17dd9ab89" xlink:to="loc_us-gaap_CostsAndExpensesAbstract_d5f6c0e8-1d15-46cd-9db8-3496ed9a74c8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSold_8005d94f-fa53-4cf3-a188-1be641724b8b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CostOfGoodsAndServicesSold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_d5f6c0e8-1d15-46cd-9db8-3496ed9a74c8" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSold_8005d94f-fa53-4cf3-a188-1be641724b8b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingCostsAndExpenses_c7f4e4af-10c2-452c-85dd-5cb6ecdf460f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingCostsAndExpenses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_d5f6c0e8-1d15-46cd-9db8-3496ed9a74c8" xlink:to="loc_us-gaap_OperatingCostsAndExpenses_c7f4e4af-10c2-452c-85dd-5cb6ecdf460f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpense_2b95c814-2e21-4dc2-9086-3ac5e3f3cfee" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GeneralAndAdministrativeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_d5f6c0e8-1d15-46cd-9db8-3496ed9a74c8" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpense_2b95c814-2e21-4dc2-9086-3ac5e3f3cfee" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationDepletionAndAmortization_0d150ecb-01f8-4df7-a320-d1f3e1e987cc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DepreciationDepletionAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_d5f6c0e8-1d15-46cd-9db8-3496ed9a74c8" xlink:to="loc_us-gaap_DepreciationDepletionAndAmortization_0d150ecb-01f8-4df7-a320-d1f3e1e987cc" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnSalesOfAssetsAndAssetImpairmentCharges_e74d3eae-1a9c-4377-ab1a-a810f866f48d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GainLossOnSalesOfAssetsAndAssetImpairmentCharges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_d5f6c0e8-1d15-46cd-9db8-3496ed9a74c8" xlink:to="loc_us-gaap_GainLossOnSalesOfAssetsAndAssetImpairmentCharges_e74d3eae-1a9c-4377-ab1a-a810f866f48d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillImpairmentLoss_c61d3e4e-654d-486d-9ec2-308e9c2cc5e0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GoodwillImpairmentLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_d5f6c0e8-1d15-46cd-9db8-3496ed9a74c8" xlink:to="loc_us-gaap_GoodwillImpairmentLoss_c61d3e4e-654d-486d-9ec2-308e9c2cc5e0" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostsAndExpenses_1ab8a5b6-919b-4838-b037-49dc9d38591a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CostsAndExpenses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_d5f6c0e8-1d15-46cd-9db8-3496ed9a74c8" xlink:to="loc_us-gaap_CostsAndExpenses_1ab8a5b6-919b-4838-b037-49dc9d38591a" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_ad9bdb8e-b54c-4f07-9155-0d822586b34c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_44806068-3ae6-4c07-b845-47b17dd9ab89" xlink:to="loc_us-gaap_OperatingIncomeLoss_ad9bdb8e-b54c-4f07-9155-0d822586b34c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonoperatingIncomeExpenseAbstract_9f413004-fa8b-4051-ada9-b43a9ab5fbd2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NonoperatingIncomeExpenseAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_44806068-3ae6-4c07-b845-47b17dd9ab89" xlink:to="loc_us-gaap_NonoperatingIncomeExpenseAbstract_9f413004-fa8b-4051-ada9-b43a9ab5fbd2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromEquityMethodInvestments_72d243b9-b8ce-4fae-a2ab-0a8759797895" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeLossFromEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_9f413004-fa8b-4051-ada9-b43a9ab5fbd2" xlink:to="loc_us-gaap_IncomeLossFromEquityMethodInvestments_72d243b9-b8ce-4fae-a2ab-0a8759797895" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_GainOnImpairmentOfInvestmentsInUnconsolidatedEntitiesNet_d09ccb0e-0339-4b01-812f-e00cb0f77885" xlink:href="paa-20211231.xsd#paa_GainOnImpairmentOfInvestmentsInUnconsolidatedEntitiesNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_9f413004-fa8b-4051-ada9-b43a9ab5fbd2" xlink:to="loc_paa_GainOnImpairmentOfInvestmentsInUnconsolidatedEntitiesNet_d09ccb0e-0339-4b01-812f-e00cb0f77885" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpense_edff8771-81ba-4938-ac37-394b1177c0cc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_9f413004-fa8b-4051-ada9-b43a9ab5fbd2" xlink:to="loc_us-gaap_InterestExpense_edff8771-81ba-4938-ac37-394b1177c0cc" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_2c7c52be-3208-431e-8532-fffb6ab49d75" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherNonoperatingIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_9f413004-fa8b-4051-ada9-b43a9ab5fbd2" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_2c7c52be-3208-431e-8532-fffb6ab49d75" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_f23fcaeb-4433-45e9-bb59-67117b1216e7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_44806068-3ae6-4c07-b845-47b17dd9ab89" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_f23fcaeb-4433-45e9-bb59-67117b1216e7" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CurrentIncomeTaxExpenseBenefit_aaad1d84-7b00-41cd-a5d5-ad34dafa805f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CurrentIncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_44806068-3ae6-4c07-b845-47b17dd9ab89" xlink:to="loc_us-gaap_CurrentIncomeTaxExpenseBenefit_aaad1d84-7b00-41cd-a5d5-ad34dafa805f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxExpenseBenefit_8e0e5942-4b8c-4659-89d0-ebbebc636b04" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredIncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_44806068-3ae6-4c07-b845-47b17dd9ab89" xlink:to="loc_us-gaap_DeferredIncomeTaxExpenseBenefit_8e0e5942-4b8c-4659-89d0-ebbebc636b04" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_3b681db7-150c-420e-b676-0017efabdb07" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_44806068-3ae6-4c07-b845-47b17dd9ab89" xlink:to="loc_us-gaap_ProfitLoss_3b681db7-150c-420e-b676-0017efabdb07" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_0b539422-888b-4b73-911f-4e5a0316ed6c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLossAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_44806068-3ae6-4c07-b845-47b17dd9ab89" xlink:to="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_0b539422-888b-4b73-911f-4e5a0316ed6c" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_c0635917-6895-4c88-a15c-2b5baf6bb0cf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_44806068-3ae6-4c07-b845-47b17dd9ab89" xlink:to="loc_us-gaap_NetIncomeLoss_c0635917-6895-4c88-a15c-2b5baf6bb0cf" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerUnitAbstract_a0a78c05-f8b3-44a9-bfc7-9db29cbbc2f5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EarningsPerUnitAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_44806068-3ae6-4c07-b845-47b17dd9ab89" xlink:to="loc_us-gaap_EarningsPerUnitAbstract_a0a78c05-f8b3-44a9-bfc7-9db29cbbc2f5" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_NetIncomeLossAllocatedtoCommonUnitholdersBasic_7dd628ce-efcf-4f07-bc65-f0acc8e564ad" xlink:href="paa-20211231.xsd#paa_NetIncomeLossAllocatedtoCommonUnitholdersBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerUnitAbstract_a0a78c05-f8b3-44a9-bfc7-9db29cbbc2f5" xlink:to="loc_paa_NetIncomeLossAllocatedtoCommonUnitholdersBasic_7dd628ce-efcf-4f07-bc65-f0acc8e564ad" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageLimitedPartnershipUnitsOutstanding_d9146598-3c59-452b-91de-8ad1905aed7d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_WeightedAverageLimitedPartnershipUnitsOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerUnitAbstract_a0a78c05-f8b3-44a9-bfc7-9db29cbbc2f5" xlink:to="loc_us-gaap_WeightedAverageLimitedPartnershipUnitsOutstanding_d9146598-3c59-452b-91de-8ad1905aed7d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossPerOutstandingLimitedPartnershipUnitBasicNetOfTax_43113a10-c883-4c0d-be69-200effe31ce0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLossPerOutstandingLimitedPartnershipUnitBasicNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerUnitAbstract_a0a78c05-f8b3-44a9-bfc7-9db29cbbc2f5" xlink:to="loc_us-gaap_NetIncomeLossPerOutstandingLimitedPartnershipUnitBasicNetOfTax_43113a10-c883-4c0d-be69-200effe31ce0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_NetIncomeLossAllocatedtoCommonUnitholdersDiluted_801be3b0-4dd6-4a91-b137-8c0f8531006d" xlink:href="paa-20211231.xsd#paa_NetIncomeLossAllocatedtoCommonUnitholdersDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerUnitAbstract_a0a78c05-f8b3-44a9-bfc7-9db29cbbc2f5" xlink:to="loc_paa_NetIncomeLossAllocatedtoCommonUnitholdersDiluted_801be3b0-4dd6-4a91-b137-8c0f8531006d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageLimitedPartnershipUnitsOutstandingDiluted_d06c94e2-aa20-4aef-970d-869cd736f5c0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_WeightedAverageLimitedPartnershipUnitsOutstandingDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerUnitAbstract_a0a78c05-f8b3-44a9-bfc7-9db29cbbc2f5" xlink:to="loc_us-gaap_WeightedAverageLimitedPartnershipUnitsOutstandingDiluted_d06c94e2-aa20-4aef-970d-869cd736f5c0" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossNetOfTaxPerOutstandingLimitedPartnershipUnitDiluted_ce7ade96-bb29-4672-95d3-8a436d140c34" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLossNetOfTaxPerOutstandingLimitedPartnershipUnitDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerUnitAbstract_a0a78c05-f8b3-44a9-bfc7-9db29cbbc2f5" xlink:to="loc_us-gaap_NetIncomeLossNetOfTaxPerOutstandingLimitedPartnershipUnitDiluted_ce7ade96-bb29-4672-95d3-8a436d140c34" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_68eebc6f-362a-4088-bf45-f44ea97853f6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_44806068-3ae6-4c07-b845-47b17dd9ab89" xlink:to="loc_us-gaap_StatementTable_68eebc6f-362a-4088-bf45-f44ea97853f6" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_b155f754-499f-4271-add3-e6062aa03f88" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_68eebc6f-362a-4088-bf45-f44ea97853f6" xlink:to="loc_srt_ProductOrServiceAxis_b155f754-499f-4271-add3-e6062aa03f88" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_b155f754-499f-4271-add3-e6062aa03f88_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_b155f754-499f-4271-add3-e6062aa03f88" xlink:to="loc_srt_ProductsAndServicesDomain_b155f754-499f-4271-add3-e6062aa03f88_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_ac9d117e-fe98-4088-b903-9ac6952b1b3d" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_b155f754-499f-4271-add3-e6062aa03f88" xlink:to="loc_srt_ProductsAndServicesDomain_ac9d117e-fe98-4088-b903-9ac6952b1b3d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProductMember_d48ba071-058d-443e-8605-0bb86fd56ecc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProductMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_ac9d117e-fe98-4088-b903-9ac6952b1b3d" xlink:to="loc_us-gaap_ProductMember_d48ba071-058d-443e-8605-0bb86fd56ecc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ServiceMember_48ecfdfd-3e68-4c5f-ba86-b75a05f32119" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ServiceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_ac9d117e-fe98-4088-b903-9ac6952b1b3d" xlink:to="loc_us-gaap_ServiceMember_48ecfdfd-3e68-4c5f-ba86-b75a05f32119" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_5781f8a7-e04d-4d62-877d-34f0a4fb87b9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountByClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_68eebc6f-362a-4088-bf45-f44ea97853f6" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_5781f8a7-e04d-4d62-877d-34f0a4fb87b9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_5781f8a7-e04d-4d62-877d-34f0a4fb87b9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_5781f8a7-e04d-4d62-877d-34f0a4fb87b9" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_5781f8a7-e04d-4d62-877d-34f0a4fb87b9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_1b862dd8-0641-487c-9f40-bbb8fad920f5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_5781f8a7-e04d-4d62-877d-34f0a4fb87b9" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_1b862dd8-0641-487c-9f40-bbb8fad920f5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_CommonUnitsMember_8d4b1587-644f-47cd-8359-b7cccad8ccf2" xlink:href="paa-20211231.xsd#paa_CommonUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_1b862dd8-0641-487c-9f40-bbb8fad920f5" xlink:to="loc_paa_CommonUnitsMember_8d4b1587-644f-47cd-8359-b7cccad8ccf2" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/CONSOLIDATEDSTATEMENTSOFCHANGESINACCUMULATEDOTHERCOMPREHENSIVEINCOMELOSS" xlink:type="simple" xlink:href="paa-20211231.xsd#CONSOLIDATEDSTATEMENTSOFCHANGESINACCUMULATEDOTHERCOMPREHENSIVEINCOMELOSS"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/CONSOLIDATEDSTATEMENTSOFCHANGESINACCUMULATEDOTHERCOMPREHENSIVEINCOMELOSS" xlink:type="extended" id="i1f56a05bbafd4580b2277b43a7b5376d_CONSOLIDATEDSTATEMENTSOFCHANGESINACCUMULATEDOTHERCOMPREHENSIVEINCOMELOSS">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_60676860-736f-4bb1-b104-adae1fd4d64d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest_c740f9f8-43cb-4d7d-a38d-c6b56d170d81" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_60676860-736f-4bb1-b104-adae1fd4d64d" xlink:to="loc_us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest_c740f9f8-43cb-4d7d-a38d-c6b56d170d81" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract_851b217a-138a-4585-9df7-d378de9c0c49" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_60676860-736f-4bb1-b104-adae1fd4d64d" xlink:to="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract_851b217a-138a-4585-9df7-d378de9c0c49" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationAfterTax_24dd1cbd-3573-4a81-a65a-0483fad4a761" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationAfterTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract_851b217a-138a-4585-9df7-d378de9c0c49" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationAfterTax_24dd1cbd-3573-4a81-a65a-0483fad4a761" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax_4164e4a3-1fde-4c5e-bf9f-0a34bc63b0b5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract_851b217a-138a-4585-9df7-d378de9c0c49" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax_4164e4a3-1fde-4c5e-bf9f-0a34bc63b0b5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax_d801b2b0-5647-4148-a169-1b0b6cf5a01f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract_851b217a-138a-4585-9df7-d378de9c0c49" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax_d801b2b0-5647-4148-a169-1b0b6cf5a01f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeOtherNetOfTax_edece0ce-c448-4081-aa61-029cab813338" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeOtherNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract_851b217a-138a-4585-9df7-d378de9c0c49" xlink:to="loc_us-gaap_OtherComprehensiveIncomeOtherNetOfTax_edece0ce-c448-4081-aa61-029cab813338" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_1f4cde72-7129-45b8-98b5-4fae1c46730e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract_851b217a-138a-4585-9df7-d378de9c0c49" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_1f4cde72-7129-45b8-98b5-4fae1c46730e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest_f1959fd2-8006-4043-b186-31ef7132e053" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_1ea00e33-7e73-4f4f-b7b4-b54b39b08976" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_60676860-736f-4bb1-b104-adae1fd4d64d" xlink:to="loc_us-gaap_StatementTable_1ea00e33-7e73-4f4f-b7b4-b54b39b08976" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerCapitalComponentsAxis_8455d51b-e394-450d-b37a-59085844446a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnerCapitalComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_1ea00e33-7e73-4f4f-b7b4-b54b39b08976" xlink:to="loc_us-gaap_PartnerCapitalComponentsAxis_8455d51b-e394-450d-b37a-59085844446a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerCapitalComponentsDomain_8455d51b-e394-450d-b37a-59085844446a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnerCapitalComponentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PartnerCapitalComponentsAxis_8455d51b-e394-450d-b37a-59085844446a" xlink:to="loc_us-gaap_PartnerCapitalComponentsDomain_8455d51b-e394-450d-b37a-59085844446a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerCapitalComponentsDomain_9ca1f29e-e815-4c58-a044-9bf515d2cfa7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnerCapitalComponentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PartnerCapitalComponentsAxis_8455d51b-e394-450d-b37a-59085844446a" xlink:to="loc_us-gaap_PartnerCapitalComponentsDomain_9ca1f29e-e815-4c58-a044-9bf515d2cfa7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedGainLossCashFlowHedgeIncludingNoncontrollingInterestMember_9f31d205-fc54-45aa-8836-55ed9a540ea4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedGainLossCashFlowHedgeIncludingNoncontrollingInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnerCapitalComponentsDomain_9ca1f29e-e815-4c58-a044-9bf515d2cfa7" xlink:to="loc_us-gaap_AccumulatedGainLossCashFlowHedgeIncludingNoncontrollingInterestMember_9f31d205-fc54-45aa-8836-55ed9a540ea4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedForeignCurrencyAdjustmentIncludingPortionAttributableToNoncontrollingInterestMember_21968220-f700-488f-830b-6d993766f5dd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedForeignCurrencyAdjustmentIncludingPortionAttributableToNoncontrollingInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnerCapitalComponentsDomain_9ca1f29e-e815-4c58-a044-9bf515d2cfa7" xlink:to="loc_us-gaap_AccumulatedForeignCurrencyAdjustmentIncludingPortionAttributableToNoncontrollingInterestMember_21968220-f700-488f-830b-6d993766f5dd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_AOCIOtherIncludingPortionAttributabletoNoncontrollingInterestMember_2f0e5a12-eae4-4d7d-909a-000c7cc8ea6f" xlink:href="paa-20211231.xsd#paa_AOCIOtherIncludingPortionAttributabletoNoncontrollingInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnerCapitalComponentsDomain_9ca1f29e-e815-4c58-a044-9bf515d2cfa7" xlink:to="loc_paa_AOCIOtherIncludingPortionAttributabletoNoncontrollingInterestMember_2f0e5a12-eae4-4d7d-909a-000c7cc8ea6f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AociIncludingPortionAttributableToNoncontrollingInterestMember_4878392f-3a97-4946-b8e1-a06156fc2ea5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AociIncludingPortionAttributableToNoncontrollingInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnerCapitalComponentsDomain_9ca1f29e-e815-4c58-a044-9bf515d2cfa7" xlink:to="loc_us-gaap_AociIncludingPortionAttributableToNoncontrollingInterestMember_4878392f-3a97-4946-b8e1-a06156fc2ea5" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/CONSOLIDATEDSTATEMENTSOFCASHFLOWS" xlink:type="simple" xlink:href="paa-20211231.xsd#CONSOLIDATEDSTATEMENTSOFCASHFLOWS"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/CONSOLIDATEDSTATEMENTSOFCASHFLOWS" xlink:type="extended" id="i4a257a5d94ae443e890898cc1ed3362b_CONSOLIDATEDSTATEMENTSOFCASHFLOWS">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_5cfde8b6-69ee-4a79-89ec-52129acf1d44" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract_59d58758-17a1-4708-8239-487321d133be" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5cfde8b6-69ee-4a79-89ec-52129acf1d44" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract_59d58758-17a1-4708-8239-487321d133be" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_48165d75-28cd-4c77-8891-fed2b8b92a90" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract_59d58758-17a1-4708-8239-487321d133be" xlink:to="loc_us-gaap_ProfitLoss_48165d75-28cd-4c77-8891-fed2b8b92a90" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_9fad7e1b-41eb-42ff-aacd-c388eacf3a6b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract_59d58758-17a1-4708-8239-487321d133be" xlink:to="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_9fad7e1b-41eb-42ff-aacd-c388eacf3a6b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationDepletionAndAmortization_97c22fef-5d03-4e9e-b357-54553c3518a0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DepreciationDepletionAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_9fad7e1b-41eb-42ff-aacd-c388eacf3a6b" xlink:to="loc_us-gaap_DepreciationDepletionAndAmortization_97c22fef-5d03-4e9e-b357-54553c3518a0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnSalesOfAssetsAndAssetImpairmentCharges_aeab1066-3e6a-43e7-b6dd-49e55ff4c99d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GainLossOnSalesOfAssetsAndAssetImpairmentCharges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_9fad7e1b-41eb-42ff-aacd-c388eacf3a6b" xlink:to="loc_us-gaap_GainLossOnSalesOfAssetsAndAssetImpairmentCharges_aeab1066-3e6a-43e7-b6dd-49e55ff4c99d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillImpairmentLoss_1ae58407-8045-4c79-a265-490d2d8a991f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GoodwillImpairmentLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_9fad7e1b-41eb-42ff-aacd-c388eacf3a6b" xlink:to="loc_us-gaap_GoodwillImpairmentLoss_1ae58407-8045-4c79-a265-490d2d8a991f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_8cf4294b-c49c-44b1-9c9a-677d8c3d623b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_9fad7e1b-41eb-42ff-aacd-c388eacf3a6b" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_8cf4294b-c49c-44b1-9c9a-677d8c3d623b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryWriteDown_13421153-7ced-4f51-a33e-87c4d1596e51" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InventoryWriteDown"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_9fad7e1b-41eb-42ff-aacd-c388eacf3a6b" xlink:to="loc_us-gaap_InventoryWriteDown_13421153-7ced-4f51-a33e-87c4d1596e51" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxExpenseBenefit_b90a03ae-1f25-4a56-b6c9-838969ae87b0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredIncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_9fad7e1b-41eb-42ff-aacd-c388eacf3a6b" xlink:to="loc_us-gaap_DeferredIncomeTaxExpenseBenefit_b90a03ae-1f25-4a56-b6c9-838969ae87b0" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_NetCashPaidReceivedforTerminatedHedgingInstruments_07e267f9-1e02-48df-8cb0-5d7ab2c76637" xlink:href="paa-20211231.xsd#paa_NetCashPaidReceivedforTerminatedHedgingInstruments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_9fad7e1b-41eb-42ff-aacd-c388eacf3a6b" xlink:to="loc_paa_NetCashPaidReceivedforTerminatedHedgingInstruments_07e267f9-1e02-48df-8cb0-5d7ab2c76637" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromEquityMethodInvestments_4f6a0ad1-0f60-42dc-a16f-63c65bbca89d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeLossFromEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_9fad7e1b-41eb-42ff-aacd-c388eacf3a6b" xlink:to="loc_us-gaap_IncomeLossFromEquityMethodInvestments_4f6a0ad1-0f60-42dc-a16f-63c65bbca89d" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentDividendsOrDistributions_e95bc6f3-69f9-4d3f-9339-ae8d262457c5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityMethodInvestmentDividendsOrDistributions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_9fad7e1b-41eb-42ff-aacd-c388eacf3a6b" xlink:to="loc_us-gaap_EquityMethodInvestmentDividendsOrDistributions_e95bc6f3-69f9-4d3f-9339-ae8d262457c5" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_GainOnImpairmentOfInvestmentsInUnconsolidatedEntitiesNet_ecabe316-bebc-4ca7-b4d3-965118c31a2b" xlink:href="paa-20211231.xsd#paa_GainOnImpairmentOfInvestmentsInUnconsolidatedEntitiesNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_9fad7e1b-41eb-42ff-aacd-c388eacf3a6b" xlink:to="loc_paa_GainOnImpairmentOfInvestmentsInUnconsolidatedEntitiesNet_ecabe316-bebc-4ca7-b4d3-965118c31a2b" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNoncashIncomeExpense_ad80b281-ec4c-4473-aee2-84257b5eafd8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherNoncashIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_9fad7e1b-41eb-42ff-aacd-c388eacf3a6b" xlink:to="loc_us-gaap_OtherNoncashIncomeExpense_ad80b281-ec4c-4473-aee2-84257b5eafd8" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_a27a9542-f5ab-40f2-b536-eeb4a28fe69f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInOperatingCapitalAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_9fad7e1b-41eb-42ff-aacd-c388eacf3a6b" xlink:to="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_a27a9542-f5ab-40f2-b536-eeb4a28fe69f" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsAndOtherReceivables_5d961d85-f6f2-424e-8ec9-afa7d3cc19a6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsAndOtherReceivables"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_a27a9542-f5ab-40f2-b536-eeb4a28fe69f" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsAndOtherReceivables_5d961d85-f6f2-424e-8ec9-afa7d3cc19a6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInInventories_db291918-8652-403d-899b-08bb4feeb2c2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInInventories"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_a27a9542-f5ab-40f2-b536-eeb4a28fe69f" xlink:to="loc_us-gaap_IncreaseDecreaseInInventories_db291918-8652-403d-899b-08bb4feeb2c2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities_5566e95b-abb7-4802-aae0-f790c9a1f4eb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_a27a9542-f5ab-40f2-b536-eeb4a28fe69f" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities_5566e95b-abb7-4802-aae0-f790c9a1f4eb" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_ae725158-71ec-4465-ae41-4329c4cfe714" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_9fad7e1b-41eb-42ff-aacd-c388eacf3a6b" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_ae725158-71ec-4465-ae41-4329c4cfe714" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract_56b13a2e-30f0-450a-816d-785d38c726cb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5cfde8b6-69ee-4a79-89ec-52129acf1d44" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract_56b13a2e-30f0-450a-816d-785d38c726cb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireBusinessesAndInterestInAffiliates_430fef75-52cb-4da4-a86f-a5929a49c63b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesAndInterestInAffiliates"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract_56b13a2e-30f0-450a-816d-785d38c726cb" xlink:to="loc_us-gaap_PaymentsToAcquireBusinessesAndInterestInAffiliates_430fef75-52cb-4da4-a86f-a5929a49c63b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_CapitalContributionsToEquityMethodInvestees_a2b34bef-344d-466d-9b1c-cbdce2db5488" xlink:href="paa-20211231.xsd#paa_CapitalContributionsToEquityMethodInvestees"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract_56b13a2e-30f0-450a-816d-785d38c726cb" xlink:to="loc_paa_CapitalContributionsToEquityMethodInvestees_a2b34bef-344d-466d-9b1c-cbdce2db5488" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_f9b8fa7f-463f-45cb-a1b2-2339bb11de1d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract_56b13a2e-30f0-450a-816d-785d38c726cb" xlink:to="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_f9b8fa7f-463f-45cb-a1b2-2339bb11de1d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromSaleOfProductiveAssets_4c53ba2f-d369-4350-b9d9-4d2670d2953b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromSaleOfProductiveAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract_56b13a2e-30f0-450a-816d-785d38c726cb" xlink:to="loc_us-gaap_ProceedsFromSaleOfProductiveAssets_4c53ba2f-d369-4350-b9d9-4d2670d2953b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsForProceedsFromOtherInvestingActivities_a9f7e038-04d2-4dcf-a340-93fe2292573c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentsForProceedsFromOtherInvestingActivities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract_56b13a2e-30f0-450a-816d-785d38c726cb" xlink:to="loc_us-gaap_PaymentsForProceedsFromOtherInvestingActivities_a9f7e038-04d2-4dcf-a340-93fe2292573c" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_371400a9-40d2-4215-ba4e-73a90f96d825" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract_56b13a2e-30f0-450a-816d-785d38c726cb" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_371400a9-40d2-4215-ba4e-73a90f96d825" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract_cd72e1df-5478-4315-beb5-c7b4b411b5b5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5cfde8b6-69ee-4a79-89ec-52129acf1d44" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract_cd72e1df-5478-4315-beb5-c7b4b411b5b5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromRepaymentsOfCommercialPaper_cbf741d9-84bb-4dbf-9ab2-13ea4f180e6d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromRepaymentsOfCommercialPaper"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract_cd72e1df-5478-4315-beb5-c7b4b411b5b5" xlink:to="loc_us-gaap_ProceedsFromRepaymentsOfCommercialPaper_cbf741d9-84bb-4dbf-9ab2-13ea4f180e6d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_NetProceedsFromRepaymentsOfHedgedInventoryFacility_43b98a35-4931-4a2c-8050-c9e1a557775d" xlink:href="paa-20211231.xsd#paa_NetProceedsFromRepaymentsOfHedgedInventoryFacility"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract_cd72e1df-5478-4315-beb5-c7b4b411b5b5" xlink:to="loc_paa_NetProceedsFromRepaymentsOfHedgedInventoryFacility_43b98a35-4931-4a2c-8050-c9e1a557775d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfSecuredDebt_7e645016-a1d8-42e4-902b-d47f8f71171d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RepaymentsOfSecuredDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract_cd72e1df-5478-4315-beb5-c7b4b411b5b5" xlink:to="loc_us-gaap_RepaymentsOfSecuredDebt_7e645016-a1d8-42e4-902b-d47f8f71171d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfSeniorLongTermDebt_ed6e5971-37d2-48e2-a7fc-7088492de72b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromIssuanceOfSeniorLongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract_cd72e1df-5478-4315-beb5-c7b4b411b5b5" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfSeniorLongTermDebt_ed6e5971-37d2-48e2-a7fc-7088492de72b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfSeniorDebt_494a9477-a6a8-4c61-88b6-69cc17a8adad" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RepaymentsOfSeniorDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract_cd72e1df-5478-4315-beb5-c7b4b411b5b5" xlink:to="loc_us-gaap_RepaymentsOfSeniorDebt_494a9477-a6a8-4c61-88b6-69cc17a8adad" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsForRepurchaseOfCommonStock_9d879deb-9468-4277-9ea9-7c47ed0e5f95" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentsForRepurchaseOfCommonStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract_cd72e1df-5478-4315-beb5-c7b4b411b5b5" xlink:to="loc_us-gaap_PaymentsForRepurchaseOfCommonStock_9d879deb-9468-4277-9ea9-7c47ed0e5f95" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DistributionMadeToLimitedPartnerCashDistributionsPaid_069267be-079b-4869-8c0e-82db714c2dd8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DistributionMadeToLimitedPartnerCashDistributionsPaid"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract_cd72e1df-5478-4315-beb5-c7b4b411b5b5" xlink:to="loc_us-gaap_DistributionMadeToLimitedPartnerCashDistributionsPaid_069267be-079b-4869-8c0e-82db714c2dd8" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromMinorityShareholders_81532f44-1aa2-411e-9183-089572f73fd0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromMinorityShareholders"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract_cd72e1df-5478-4315-beb5-c7b4b411b5b5" xlink:to="loc_us-gaap_ProceedsFromMinorityShareholders_81532f44-1aa2-411e-9183-089572f73fd0" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromPaymentsForOtherFinancingActivities_5de11c10-0046-49e0-a457-602ef4ba7465" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromPaymentsForOtherFinancingActivities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract_cd72e1df-5478-4315-beb5-c7b4b411b5b5" xlink:to="loc_us-gaap_ProceedsFromPaymentsForOtherFinancingActivities_5de11c10-0046-49e0-a457-602ef4ba7465" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_1006d531-4ba2-4299-ac2c-6b4ba3d191be" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract_cd72e1df-5478-4315-beb5-c7b4b411b5b5" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_1006d531-4ba2-4299-ac2c-6b4ba3d191be" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_88b05eaf-bf11-42be-b2a9-98049cc6a7c9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5cfde8b6-69ee-4a79-89ec-52129acf1d44" xlink:to="loc_us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_88b05eaf-bf11-42be-b2a9-98049cc6a7c9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_ae65d1f1-fa95-4b9d-900c-52457a2ab368" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5cfde8b6-69ee-4a79-89ec-52129acf1d44" xlink:to="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_ae65d1f1-fa95-4b9d-900c-52457a2ab368" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_e1546ed5-90c2-4e15-9c56-d2964775a088" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5cfde8b6-69ee-4a79-89ec-52129acf1d44" xlink:to="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_e1546ed5-90c2-4e15-9c56-d2964775a088" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_9a43ac3c-c121-4427-bca2-647ee58c7977" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SupplementalCashFlowInformationAbstract_65341d78-24d8-4245-94f9-6899d95ddd36" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SupplementalCashFlowInformationAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5cfde8b6-69ee-4a79-89ec-52129acf1d44" xlink:to="loc_us-gaap_SupplementalCashFlowInformationAbstract_65341d78-24d8-4245-94f9-6899d95ddd36" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestPaidNet_eeb5163f-126c-48ed-8fb9-c32db792bfa0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestPaidNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SupplementalCashFlowInformationAbstract_65341d78-24d8-4245-94f9-6899d95ddd36" xlink:to="loc_us-gaap_InterestPaidNet_eeb5163f-126c-48ed-8fb9-c32db792bfa0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxesPaidNet_c7550929-a079-4222-a1e4-667159cc3378" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxesPaidNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SupplementalCashFlowInformationAbstract_65341d78-24d8-4245-94f9-6899d95ddd36" xlink:to="loc_us-gaap_IncomeTaxesPaidNet_c7550929-a079-4222-a1e4-667159cc3378" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_0e70e697-33b3-403e-b1b8-0ee0d309a766" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_5cfde8b6-69ee-4a79-89ec-52129acf1d44" xlink:to="loc_us-gaap_StatementTable_0e70e697-33b3-403e-b1b8-0ee0d309a766" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_a6c3c7df-ed16-4eda-b2d4-939b513deb38" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountByClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_0e70e697-33b3-403e-b1b8-0ee0d309a766" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_a6c3c7df-ed16-4eda-b2d4-939b513deb38" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_a6c3c7df-ed16-4eda-b2d4-939b513deb38_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_a6c3c7df-ed16-4eda-b2d4-939b513deb38" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_a6c3c7df-ed16-4eda-b2d4-939b513deb38_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_c4fa17d2-840b-4c74-8ea7-8601173da124" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_a6c3c7df-ed16-4eda-b2d4-939b513deb38" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_c4fa17d2-840b-4c74-8ea7-8601173da124" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SeriesAPreferredUnitsMember_cf3b1248-785a-4903-b676-21300abd2327" xlink:href="paa-20211231.xsd#paa_SeriesAPreferredUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_c4fa17d2-840b-4c74-8ea7-8601173da124" xlink:to="loc_paa_SeriesAPreferredUnitsMember_cf3b1248-785a-4903-b676-21300abd2327" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SeriesBPreferredUnitsMember_a30d2cea-85f0-41fd-9f51-4bb8d6f65db3" xlink:href="paa-20211231.xsd#paa_SeriesBPreferredUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_c4fa17d2-840b-4c74-8ea7-8601173da124" xlink:to="loc_paa_SeriesBPreferredUnitsMember_a30d2cea-85f0-41fd-9f51-4bb8d6f65db3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_CommonUnitsMember_972cd4b0-2df1-45aa-b499-6f537c2e1120" xlink:href="paa-20211231.xsd#paa_CommonUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_c4fa17d2-840b-4c74-8ea7-8601173da124" xlink:to="loc_paa_CommonUnitsMember_972cd4b0-2df1-45aa-b499-6f537c2e1120" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/CONSOLIDATEDSTATEMENTSOFCHANGESINPARTNERSCAPITAL" xlink:type="simple" xlink:href="paa-20211231.xsd#CONSOLIDATEDSTATEMENTSOFCHANGESINPARTNERSCAPITAL"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/CONSOLIDATEDSTATEMENTSOFCHANGESINPARTNERSCAPITAL" xlink:type="extended" id="i34708583cb3d49579f843739d64e032d_CONSOLIDATEDSTATEMENTSOFCHANGESINPARTNERSCAPITAL">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_24c2c896-84e1-4a6a-9cac-0968769202f7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_124c119d-27f6-420c-8558-27f86f6b1a9c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInPartnersCapitalRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_24c2c896-84e1-4a6a-9cac-0968769202f7" xlink:to="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_124c119d-27f6-420c-8558-27f86f6b1a9c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest_9a673cdb-3b54-44b7-a63f-b890dfc18ff3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_124c119d-27f6-420c-8558-27f86f6b1a9c" xlink:to="loc_us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest_9a673cdb-3b54-44b7-a63f-b890dfc18ff3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_a284d1b3-7c72-4f8e-a242-16be0924d1b3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_124c119d-27f6-420c-8558-27f86f6b1a9c" xlink:to="loc_us-gaap_ProfitLoss_a284d1b3-7c72-4f8e-a242-16be0924d1b3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapitalAccountDistributions_76549cf4-61a7-4f1e-9613-cfdce3072359" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnersCapitalAccountDistributions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_124c119d-27f6-420c-8558-27f86f6b1a9c" xlink:to="loc_us-gaap_PartnersCapitalAccountDistributions_76549cf4-61a7-4f1e-9613-cfdce3072359" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_e625a20c-41a0-4b91-a3c1-9ff7a84b0171" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_124c119d-27f6-420c-8558-27f86f6b1a9c" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_e625a20c-41a0-4b91-a3c1-9ff7a84b0171" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapitalAccountUnitBasedCompensation_b255a634-2a6f-4ba0-b3de-7b4582955e32" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnersCapitalAccountUnitBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_124c119d-27f6-420c-8558-27f86f6b1a9c" xlink:to="loc_us-gaap_PartnersCapitalAccountUnitBasedCompensation_b255a634-2a6f-4ba0-b3de-7b4582955e32" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedDuringPeriodValue_77b9c64a-745c-433e-8250-668b12c67cfb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockRepurchasedDuringPeriodValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_124c119d-27f6-420c-8558-27f86f6b1a9c" xlink:to="loc_us-gaap_StockRepurchasedDuringPeriodValue_77b9c64a-745c-433e-8250-668b12c67cfb" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapitalAccountContributions_9f04b469-2d10-46d6-b53b-5168f8b045fe" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnersCapitalAccountContributions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_124c119d-27f6-420c-8558-27f86f6b1a9c" xlink:to="loc_us-gaap_PartnersCapitalAccountContributions_9f04b469-2d10-46d6-b53b-5168f8b045fe" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestChangesSaleOfInterestByParent_1ccd3bcf-9142-4dcf-9747-fef8f9eb5afa" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestChangesSaleOfInterestByParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_124c119d-27f6-420c-8558-27f86f6b1a9c" xlink:to="loc_us-gaap_ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestChangesSaleOfInterestByParent_1ccd3bcf-9142-4dcf-9747-fef8f9eb5afa" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapitalAccountAcquisitions_1c0d14e4-3742-46b2-a8a7-3a245cf34cfb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnersCapitalAccountAcquisitions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_124c119d-27f6-420c-8558-27f86f6b1a9c" xlink:to="loc_us-gaap_PartnersCapitalAccountAcquisitions_1c0d14e4-3742-46b2-a8a7-3a245cf34cfb" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapitalOther_acc73a5b-5daf-439a-b0df-a9724093ace7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnersCapitalOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_124c119d-27f6-420c-8558-27f86f6b1a9c" xlink:to="loc_us-gaap_PartnersCapitalOther_acc73a5b-5daf-439a-b0df-a9724093ace7" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest_d85a9ce1-ea23-4819-990f-cf03a9bc6dc6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_d8da4857-e32d-4de6-8dc2-16b2da6a1e86" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_24c2c896-84e1-4a6a-9cac-0968769202f7" xlink:to="loc_us-gaap_StatementTable_d8da4857-e32d-4de6-8dc2-16b2da6a1e86" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_492afd17-eadb-4931-b196-5e64802868a2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountByClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_d8da4857-e32d-4de6-8dc2-16b2da6a1e86" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_492afd17-eadb-4931-b196-5e64802868a2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_492afd17-eadb-4931-b196-5e64802868a2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_492afd17-eadb-4931-b196-5e64802868a2" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_492afd17-eadb-4931-b196-5e64802868a2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_c2104bf2-c0a9-402e-89a8-11c233090f7b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_492afd17-eadb-4931-b196-5e64802868a2" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_c2104bf2-c0a9-402e-89a8-11c233090f7b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SeriesAPreferredUnitsMember_1cb1a4b5-4d97-4b35-ada3-76d9999ab2f8" xlink:href="paa-20211231.xsd#paa_SeriesAPreferredUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_c2104bf2-c0a9-402e-89a8-11c233090f7b" xlink:to="loc_paa_SeriesAPreferredUnitsMember_1cb1a4b5-4d97-4b35-ada3-76d9999ab2f8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SeriesBPreferredUnitsMember_6358437b-bf5f-471f-b9d9-6b21982cc2e3" xlink:href="paa-20211231.xsd#paa_SeriesBPreferredUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_c2104bf2-c0a9-402e-89a8-11c233090f7b" xlink:to="loc_paa_SeriesBPreferredUnitsMember_6358437b-bf5f-471f-b9d9-6b21982cc2e3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_CommonUnitsMember_624fddb4-7865-4f26-80b7-99fd16c60a50" xlink:href="paa-20211231.xsd#paa_CommonUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_c2104bf2-c0a9-402e-89a8-11c233090f7b" xlink:to="loc_paa_CommonUnitsMember_624fddb4-7865-4f26-80b7-99fd16c60a50" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_d6785a82-cc3d-4061-956b-3464d5cfe15f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_d8da4857-e32d-4de6-8dc2-16b2da6a1e86" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_d6785a82-cc3d-4061-956b-3464d5cfe15f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_d6785a82-cc3d-4061-956b-3464d5cfe15f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_d6785a82-cc3d-4061-956b-3464d5cfe15f" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_d6785a82-cc3d-4061-956b-3464d5cfe15f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_bacfc880-5491-40ce-b642-e4fc702b1ff0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_d6785a82-cc3d-4061-956b-3464d5cfe15f" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_bacfc880-5491-40ce-b642-e4fc702b1ff0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnerMember_a4880627-2144-4a75-bb94-90099b3edee4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_bacfc880-5491-40ce-b642-e4fc702b1ff0" xlink:to="loc_us-gaap_LimitedPartnerMember_a4880627-2144-4a75-bb94-90099b3edee4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerCapitalComponentsAxis_6f435902-aee4-40c8-aeb9-61d2cf6cbf9a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnerCapitalComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_d8da4857-e32d-4de6-8dc2-16b2da6a1e86" xlink:to="loc_us-gaap_PartnerCapitalComponentsAxis_6f435902-aee4-40c8-aeb9-61d2cf6cbf9a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerCapitalComponentsDomain_6f435902-aee4-40c8-aeb9-61d2cf6cbf9a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnerCapitalComponentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PartnerCapitalComponentsAxis_6f435902-aee4-40c8-aeb9-61d2cf6cbf9a" xlink:to="loc_us-gaap_PartnerCapitalComponentsDomain_6f435902-aee4-40c8-aeb9-61d2cf6cbf9a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerCapitalComponentsDomain_70019240-67c5-464c-ae5f-10acc8e5e3de" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnerCapitalComponentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PartnerCapitalComponentsAxis_6f435902-aee4-40c8-aeb9-61d2cf6cbf9a" xlink:to="loc_us-gaap_PartnerCapitalComponentsDomain_70019240-67c5-464c-ae5f-10acc8e5e3de" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ParentMember_a20d8a9e-3629-4290-af8d-8d6138c59f32" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ParentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnerCapitalComponentsDomain_70019240-67c5-464c-ae5f-10acc8e5e3de" xlink:to="loc_us-gaap_ParentMember_a20d8a9e-3629-4290-af8d-8d6138c59f32" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncontrollingInterestMember_f2345b42-132d-4866-b5dd-9f533dee20eb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NoncontrollingInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnerCapitalComponentsDomain_70019240-67c5-464c-ae5f-10acc8e5e3de" xlink:to="loc_us-gaap_NoncontrollingInterestMember_f2345b42-132d-4866-b5dd-9f533dee20eb" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/OrganizationandBasisofConsolidationandPresentationDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#OrganizationandBasisofConsolidationandPresentationDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/OrganizationandBasisofConsolidationandPresentationDetails" xlink:type="extended" id="i4b996d20377b406c821ca9f3d32e6633_OrganizationandBasisofConsolidationandPresentationDetails">
    <link:loc xlink:type="locator" xlink:label="loc_paa_OrganizationAndBasisOfPresentationLineItems_b5eac462-9821-4e02-8b2d-60507f420f3d" xlink:href="paa-20211231.xsd#paa_OrganizationAndBasisOfPresentationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfOperatingSegments_760c622a-db32-46c2-88ce-b1282f6f2a2a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NumberOfOperatingSegments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_OrganizationAndBasisOfPresentationLineItems_b5eac462-9821-4e02-8b2d-60507f420f3d" xlink:to="loc_us-gaap_NumberOfOperatingSegments_760c622a-db32-46c2-88ce-b1282f6f2a2a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_LimitedLiabilityCompanyLLCorLimitedPartnershipLPMembersorLimitedPartnersOwnershipInterestUnits_1325cb36-58e9-40f4-9832-5ea3be48cb73" xlink:href="paa-20211231.xsd#paa_LimitedLiabilityCompanyLLCorLimitedPartnershipLPMembersorLimitedPartnersOwnershipInterestUnits"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_OrganizationAndBasisOfPresentationLineItems_b5eac462-9821-4e02-8b2d-60507f420f3d" xlink:to="loc_paa_LimitedLiabilityCompanyLLCorLimitedPartnershipLPMembersorLimitedPartnersOwnershipInterestUnits_1325cb36-58e9-40f4-9832-5ea3be48cb73" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPMembersOrLimitedPartnersOwnershipInterest_d71c770b-3e34-4da4-837b-343fe6547ad6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPMembersOrLimitedPartnersOwnershipInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_OrganizationAndBasisOfPresentationLineItems_b5eac462-9821-4e02-8b2d-60507f420f3d" xlink:to="loc_us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPMembersOrLimitedPartnersOwnershipInterest_d71c770b-3e34-4da4-837b-343fe6547ad6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_OrganizationConsolidationAndPresentationOfFinancialStatementsTable_ca2dd6a1-d52c-45cb-9ae6-ae6b2385f367" xlink:href="paa-20211231.xsd#paa_OrganizationConsolidationAndPresentationOfFinancialStatementsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_paa_OrganizationAndBasisOfPresentationLineItems_b5eac462-9821-4e02-8b2d-60507f420f3d" xlink:to="loc_paa_OrganizationConsolidationAndPresentationOfFinancialStatementsTable_ca2dd6a1-d52c-45cb-9ae6-ae6b2385f367" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipAxis_707a75b0-20ac-4057-bd7e-9d9734d7c134" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_OwnershipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_paa_OrganizationConsolidationAndPresentationOfFinancialStatementsTable_ca2dd6a1-d52c-45cb-9ae6-ae6b2385f367" xlink:to="loc_srt_OwnershipAxis_707a75b0-20ac-4057-bd7e-9d9734d7c134" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_707a75b0-20ac-4057-bd7e-9d9734d7c134_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_OwnershipAxis_707a75b0-20ac-4057-bd7e-9d9734d7c134" xlink:to="loc_srt_OwnershipDomain_707a75b0-20ac-4057-bd7e-9d9734d7c134_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_d2a6d052-a393-44b3-8919-c8c20b396d54" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_OwnershipAxis_707a75b0-20ac-4057-bd7e-9d9734d7c134" xlink:to="loc_srt_OwnershipDomain_d2a6d052-a393-44b3-8919-c8c20b396d54" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PlainsAapLPMember_4bbfafc6-9283-4514-853a-a68615db28d0" xlink:href="paa-20211231.xsd#paa_PlainsAapLPMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_OwnershipDomain_d2a6d052-a393-44b3-8919-c8c20b396d54" xlink:to="loc_paa_PlainsAapLPMember_4bbfafc6-9283-4514-853a-a68615db28d0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PlainsAllAmericanPipelineLPMember_3ff0221a-08e3-4b81-b74f-6131c3050527" xlink:href="paa-20211231.xsd#paa_PlainsAllAmericanPipelineLPMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_OwnershipDomain_d2a6d052-a393-44b3-8919-c8c20b396d54" xlink:to="loc_paa_PlainsAllAmericanPipelineLPMember_3ff0221a-08e3-4b81-b74f-6131c3050527" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_3da37743-d164-423e-aa68-8aaafd4d4711" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_paa_OrganizationConsolidationAndPresentationOfFinancialStatementsTable_ca2dd6a1-d52c-45cb-9ae6-ae6b2385f367" xlink:to="loc_dei_LegalEntityAxis_3da37743-d164-423e-aa68-8aaafd4d4711" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_3da37743-d164-423e-aa68-8aaafd4d4711_default" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_3da37743-d164-423e-aa68-8aaafd4d4711" xlink:to="loc_dei_EntityDomain_3da37743-d164-423e-aa68-8aaafd4d4711_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_f5a37261-c1c0-4279-a7a3-f01c7043ffac" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_3da37743-d164-423e-aa68-8aaafd4d4711" xlink:to="loc_dei_EntityDomain_f5a37261-c1c0-4279-a7a3-f01c7043ffac" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PlainsAapLPMember_f77cc204-1050-4546-b910-42dce2a0dc41" xlink:href="paa-20211231.xsd#paa_PlainsAapLPMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_f5a37261-c1c0-4279-a7a3-f01c7043ffac" xlink:to="loc_paa_PlainsAapLPMember_f77cc204-1050-4546-b910-42dce2a0dc41" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PlainsGPHoldingsLPMember_d61523c1-6820-4c13-97b8-00a96b3de6d0" xlink:href="paa-20211231.xsd#paa_PlainsGPHoldingsLPMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_f5a37261-c1c0-4279-a7a3-f01c7043ffac" xlink:to="loc_paa_PlainsGPHoldingsLPMember_d61523c1-6820-4c13-97b8-00a96b3de6d0" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/RevenuesandAccountsReceivableDisaggregationofRevenueDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#RevenuesandAccountsReceivableDisaggregationofRevenueDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/RevenuesandAccountsReceivableDisaggregationofRevenueDetails" xlink:type="extended" id="i211b8555c06e43f5a9238e0eb89f8165_RevenuesandAccountsReceivableDisaggregationofRevenueDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_78dee327-16aa-41fc-b3bd-ff1e594a91be" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_43115b02-060f-407a-9227-30cdde6bdd2a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_78dee327-16aa-41fc-b3bd-ff1e594a91be" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_43115b02-060f-407a-9227-30cdde6bdd2a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_c7df3ec2-51a7-420e-b73d-7bd23c9369fe" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisaggregationOfRevenueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_78dee327-16aa-41fc-b3bd-ff1e594a91be" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_c7df3ec2-51a7-420e-b73d-7bd23c9369fe" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_b86f6b26-096d-4f1e-a724-d535b0978c01" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_c7df3ec2-51a7-420e-b73d-7bd23c9369fe" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_b86f6b26-096d-4f1e-a724-d535b0978c01" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_b86f6b26-096d-4f1e-a724-d535b0978c01_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_b86f6b26-096d-4f1e-a724-d535b0978c01" xlink:to="loc_us-gaap_SegmentDomain_b86f6b26-096d-4f1e-a724-d535b0978c01_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_e1d41985-1911-48fa-bedc-2d5a5383c508" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_b86f6b26-096d-4f1e-a724-d535b0978c01" xlink:to="loc_us-gaap_SegmentDomain_e1d41985-1911-48fa-bedc-2d5a5383c508" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_CrudeOilSegmentMember_6e2ddd4a-2204-4e74-a64f-37e78d077671" xlink:href="paa-20211231.xsd#paa_CrudeOilSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_e1d41985-1911-48fa-bedc-2d5a5383c508" xlink:to="loc_paa_CrudeOilSegmentMember_6e2ddd4a-2204-4e74-a64f-37e78d077671" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_NaturalGasLiquidsSegmentMember_ee502dec-3639-4dd6-8dcd-23bebc27fb11" xlink:href="paa-20211231.xsd#paa_NaturalGasLiquidsSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_e1d41985-1911-48fa-bedc-2d5a5383c508" xlink:to="loc_paa_NaturalGasLiquidsSegmentMember_ee502dec-3639-4dd6-8dcd-23bebc27fb11" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_fd0fc27c-da44-4971-97ca-0981a54aac55" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_c7df3ec2-51a7-420e-b73d-7bd23c9369fe" xlink:to="loc_srt_ProductOrServiceAxis_fd0fc27c-da44-4971-97ca-0981a54aac55" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_fd0fc27c-da44-4971-97ca-0981a54aac55_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_fd0fc27c-da44-4971-97ca-0981a54aac55" xlink:to="loc_srt_ProductsAndServicesDomain_fd0fc27c-da44-4971-97ca-0981a54aac55_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_4a9d5c74-1e5b-4fc7-b301-67004ea28ff7" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_fd0fc27c-da44-4971-97ca-0981a54aac55" xlink:to="loc_srt_ProductsAndServicesDomain_4a9d5c74-1e5b-4fc7-b301-67004ea28ff7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProductMember_6550d6ce-8fb9-4598-a15e-15c90398b2d3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProductMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_4a9d5c74-1e5b-4fc7-b301-67004ea28ff7" xlink:to="loc_us-gaap_ProductMember_6550d6ce-8fb9-4598-a15e-15c90398b2d3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_TransportationRevenueMember_ef6b91cd-9b20-4f92-9d0c-9880ed24a32b" xlink:href="paa-20211231.xsd#paa_TransportationRevenueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_4a9d5c74-1e5b-4fc7-b301-67004ea28ff7" xlink:to="loc_paa_TransportationRevenueMember_ef6b91cd-9b20-4f92-9d0c-9880ed24a32b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_TerminallingStorageAndOtherRevenueMember_0d67a97e-e07c-48d8-9ea5-bc5b81b55f5d" xlink:href="paa-20211231.xsd#paa_TerminallingStorageAndOtherRevenueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_4a9d5c74-1e5b-4fc7-b301-67004ea28ff7" xlink:to="loc_paa_TerminallingStorageAndOtherRevenueMember_0d67a97e-e07c-48d8-9ea5-bc5b81b55f5d" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/RevenuesandAccountsReceivableAgreementBalancesDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#RevenuesandAccountsReceivableAgreementBalancesDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/RevenuesandAccountsReceivableAgreementBalancesDetails" xlink:type="extended" id="i4411acf1b9db4436920026085a410047_RevenuesandAccountsReceivableAgreementBalancesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_paa_ContractWithCustomerAssetAndLiabilityLineItems_13e88124-93a4-49d6-a09d-2911d89939d5" xlink:href="paa-20211231.xsd#paa_ContractWithCustomerAssetAndLiabilityLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsCurrent_98161473-8abd-4a3d-bdb9-51158515be33" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherAssetsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_ContractWithCustomerAssetAndLiabilityLineItems_13e88124-93a4-49d6-a09d-2911d89939d5" xlink:to="loc_us-gaap_OtherAssetsCurrent_98161473-8abd-4a3d-bdb9-51158515be33" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiability_ddbb054c-2af5-4c13-84ee-e729eab69b53" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_ContractWithCustomerAssetAndLiabilityLineItems_13e88124-93a4-49d6-a09d-2911d89939d5" xlink:to="loc_us-gaap_ContractWithCustomerLiability_ddbb054c-2af5-4c13-84ee-e729eab69b53" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_ContractWithCustomerAssetAndLiabilityTable_3e5338a4-651a-4f9e-b871-e9056e9f23e9" xlink:href="paa-20211231.xsd#paa_ContractWithCustomerAssetAndLiabilityTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_paa_ContractWithCustomerAssetAndLiabilityLineItems_13e88124-93a4-49d6-a09d-2911d89939d5" xlink:to="loc_paa_ContractWithCustomerAssetAndLiabilityTable_3e5338a4-651a-4f9e-b871-e9056e9f23e9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfArrangementAxis_ab85d6bb-2833-487c-ac2f-1c9d7fc117e3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TypeOfArrangementAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_paa_ContractWithCustomerAssetAndLiabilityTable_3e5338a4-651a-4f9e-b871-e9056e9f23e9" xlink:to="loc_us-gaap_TypeOfArrangementAxis_ab85d6bb-2833-487c-ac2f-1c9d7fc117e3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_ab85d6bb-2833-487c-ac2f-1c9d7fc117e3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TypeOfArrangementAxis_ab85d6bb-2833-487c-ac2f-1c9d7fc117e3" xlink:to="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_ab85d6bb-2833-487c-ac2f-1c9d7fc117e3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_30d296ef-e78e-481e-b3d3-e6aa66d83937" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TypeOfArrangementAxis_ab85d6bb-2833-487c-ac2f-1c9d7fc117e3" xlink:to="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_30d296ef-e78e-481e-b3d3-e6aa66d83937" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_CrudeOilSalesAgreementsEnteredIntoInConjunctionWIthStorageArrangementsAndFutureInventoryExchangesMember_a5f9243b-922f-4991-b885-05b12e336760" xlink:href="paa-20211231.xsd#paa_CrudeOilSalesAgreementsEnteredIntoInConjunctionWIthStorageArrangementsAndFutureInventoryExchangesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_30d296ef-e78e-481e-b3d3-e6aa66d83937" xlink:to="loc_paa_CrudeOilSalesAgreementsEnteredIntoInConjunctionWIthStorageArrangementsAndFutureInventoryExchangesMember_a5f9243b-922f-4991-b885-05b12e336760" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/RevenuesandAccountsReceivableSegmentRevenueDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#RevenuesandAccountsReceivableSegmentRevenueDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/RevenuesandAccountsReceivableSegmentRevenueDetails" xlink:type="extended" id="i57a9d73850164b93adaf4a594c38af8d_RevenuesandAccountsReceivableSegmentRevenueDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_5ab1376b-998b-487d-bb58-46d90abef83d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_24506cb1-c25d-4115-b2c5-de795bbc4ffb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_5ab1376b-998b-487d-bb58-46d90abef83d" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_24506cb1-c25d-4115-b2c5-de795bbc4ffb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueNotFromContractWithCustomer_37927296-4e12-47a3-b25b-52bb2858a5c4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueNotFromContractWithCustomer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_5ab1376b-998b-487d-bb58-46d90abef83d" xlink:to="loc_us-gaap_RevenueNotFromContractWithCustomer_37927296-4e12-47a3-b25b-52bb2858a5c4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_240f3987-5bd1-41ff-a226-35167b2d161a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_5ab1376b-998b-487d-bb58-46d90abef83d" xlink:to="loc_us-gaap_Revenues_240f3987-5bd1-41ff-a226-35167b2d161a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_e2ccd684-9a08-4547-9125-4b2d868f5037" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisaggregationOfRevenueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_5ab1376b-998b-487d-bb58-46d90abef83d" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_e2ccd684-9a08-4547-9125-4b2d868f5037" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_80d23716-9e3f-43c7-bfcc-1ef00cb2bb24" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_e2ccd684-9a08-4547-9125-4b2d868f5037" xlink:to="loc_srt_ConsolidationItemsAxis_80d23716-9e3f-43c7-bfcc-1ef00cb2bb24" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_80d23716-9e3f-43c7-bfcc-1ef00cb2bb24_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_80d23716-9e3f-43c7-bfcc-1ef00cb2bb24" xlink:to="loc_srt_ConsolidationItemsDomain_80d23716-9e3f-43c7-bfcc-1ef00cb2bb24_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_e555b4c4-81b7-48fa-b0f9-c6f7209d8df8" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_80d23716-9e3f-43c7-bfcc-1ef00cb2bb24" xlink:to="loc_srt_ConsolidationItemsDomain_e555b4c4-81b7-48fa-b0f9-c6f7209d8df8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingSegmentsMember_a1ef9a65-55a1-4792-b2a6-64954cd9a7c5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_e555b4c4-81b7-48fa-b0f9-c6f7209d8df8" xlink:to="loc_us-gaap_OperatingSegmentsMember_a1ef9a65-55a1-4792-b2a6-64954cd9a7c5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntersegmentEliminationMember_fcca75db-00ff-4784-9057-087b5aaa29d9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IntersegmentEliminationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_e555b4c4-81b7-48fa-b0f9-c6f7209d8df8" xlink:to="loc_us-gaap_IntersegmentEliminationMember_fcca75db-00ff-4784-9057-087b5aaa29d9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_bf7cb33c-e7da-415d-be11-b93931c752a9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_e2ccd684-9a08-4547-9125-4b2d868f5037" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_bf7cb33c-e7da-415d-be11-b93931c752a9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_bf7cb33c-e7da-415d-be11-b93931c752a9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_bf7cb33c-e7da-415d-be11-b93931c752a9" xlink:to="loc_us-gaap_SegmentDomain_bf7cb33c-e7da-415d-be11-b93931c752a9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_e686fc45-158f-475b-8ca6-4aef40f2cff5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_bf7cb33c-e7da-415d-be11-b93931c752a9" xlink:to="loc_us-gaap_SegmentDomain_e686fc45-158f-475b-8ca6-4aef40f2cff5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_CrudeOilSegmentMember_6b383050-bb8b-4b6e-b112-1c3a357540f3" xlink:href="paa-20211231.xsd#paa_CrudeOilSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_e686fc45-158f-475b-8ca6-4aef40f2cff5" xlink:to="loc_paa_CrudeOilSegmentMember_6b383050-bb8b-4b6e-b112-1c3a357540f3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_NaturalGasLiquidsSegmentMember_9e671db7-1203-43a5-84c8-15c0c72576c8" xlink:href="paa-20211231.xsd#paa_NaturalGasLiquidsSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_e686fc45-158f-475b-8ca6-4aef40f2cff5" xlink:to="loc_paa_NaturalGasLiquidsSegmentMember_9e671db7-1203-43a5-84c8-15c0c72576c8" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/RevenuesandAccountsReceivableCounterpartyDeficienciesDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#RevenuesandAccountsReceivableCounterpartyDeficienciesDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/RevenuesandAccountsReceivableCounterpartyDeficienciesDetails" xlink:type="extended" id="i8d84bffc5acb43d0b97b9c5885a5d191_RevenuesandAccountsReceivableCounterpartyDeficienciesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_paa_ContractWithCustomerAssetAndLiabilityLineItems_a9c1bc93-627e-4bf9-8aa4-f2e420fccaa9" xlink:href="paa-20211231.xsd#paa_ContractWithCustomerAssetAndLiabilityLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiability_b65e97ff-50b7-4721-bbf7-770be99edddf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_ContractWithCustomerAssetAndLiabilityLineItems_a9c1bc93-627e-4bf9-8aa4-f2e420fccaa9" xlink:to="loc_us-gaap_ContractWithCustomerLiability_b65e97ff-50b7-4721-bbf7-770be99edddf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_CounterpartyDeficienciesUnbilledAndUncollected_46da4be1-89ac-4c3e-b60b-b78a0417112f" xlink:href="paa-20211231.xsd#paa_CounterpartyDeficienciesUnbilledAndUncollected"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_ContractWithCustomerAssetAndLiabilityLineItems_a9c1bc93-627e-4bf9-8aa4-f2e420fccaa9" xlink:to="loc_paa_CounterpartyDeficienciesUnbilledAndUncollected_46da4be1-89ac-4c3e-b60b-b78a0417112f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_CounterpartyDeficiencies_ba0ecb39-a208-4d45-ad80-cbcece40b353" xlink:href="paa-20211231.xsd#paa_CounterpartyDeficiencies"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_ContractWithCustomerAssetAndLiabilityLineItems_a9c1bc93-627e-4bf9-8aa4-f2e420fccaa9" xlink:to="loc_paa_CounterpartyDeficiencies_ba0ecb39-a208-4d45-ad80-cbcece40b353" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_ContractWithCustomerAssetAndLiabilityTable_733529e6-81b1-44dd-875b-5da16c5a4bfd" xlink:href="paa-20211231.xsd#paa_ContractWithCustomerAssetAndLiabilityTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_paa_ContractWithCustomerAssetAndLiabilityLineItems_a9c1bc93-627e-4bf9-8aa4-f2e420fccaa9" xlink:to="loc_paa_ContractWithCustomerAssetAndLiabilityTable_733529e6-81b1-44dd-875b-5da16c5a4bfd" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfArrangementAxis_f6ea26de-cc5e-49f0-963f-11b511605922" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TypeOfArrangementAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_paa_ContractWithCustomerAssetAndLiabilityTable_733529e6-81b1-44dd-875b-5da16c5a4bfd" xlink:to="loc_us-gaap_TypeOfArrangementAxis_f6ea26de-cc5e-49f0-963f-11b511605922" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_f6ea26de-cc5e-49f0-963f-11b511605922_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TypeOfArrangementAxis_f6ea26de-cc5e-49f0-963f-11b511605922" xlink:to="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_f6ea26de-cc5e-49f0-963f-11b511605922_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_f477ddce-fd01-4415-a1bf-70d00eec4e5d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TypeOfArrangementAxis_f6ea26de-cc5e-49f0-963f-11b511605922" xlink:to="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_f477ddce-fd01-4415-a1bf-70d00eec4e5d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_MinimumVolumeCommitmentAgreementsMember_6353b10f-a89b-4fba-8009-fd7d86cf60ad" xlink:href="paa-20211231.xsd#paa_MinimumVolumeCommitmentAgreementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_f477ddce-fd01-4415-a1bf-70d00eec4e5d" xlink:to="loc_paa_MinimumVolumeCommitmentAgreementsMember_6353b10f-a89b-4fba-8009-fd7d86cf60ad" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/RevenuesandAccountsReceivableContractBalancesDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#RevenuesandAccountsReceivableContractBalancesDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/RevenuesandAccountsReceivableContractBalancesDetails" xlink:type="extended" id="i2f998bb7d301401eafb2d96d3e88720d_RevenuesandAccountsReceivableContractBalancesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_paa_ContractWithCustomerAssetAndLiabilityLineItems_40a1bcbd-d804-45d6-9a19-7a4ac83e8783" xlink:href="paa-20211231.xsd#paa_ContractWithCustomerAssetAndLiabilityLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_ChangeInContractWithCustomerLiabilityRollForward_704f62e9-cd87-4514-bb75-12843224da52" xlink:href="paa-20211231.xsd#paa_ChangeInContractWithCustomerLiabilityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_ContractWithCustomerAssetAndLiabilityLineItems_40a1bcbd-d804-45d6-9a19-7a4ac83e8783" xlink:to="loc_paa_ChangeInContractWithCustomerLiabilityRollForward_704f62e9-cd87-4514-bb75-12843224da52" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiability_a5ec777d-c812-48de-8967-3b0213b055ec" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_ChangeInContractWithCustomerLiabilityRollForward_704f62e9-cd87-4514-bb75-12843224da52" xlink:to="loc_us-gaap_ContractWithCustomerLiability_a5ec777d-c812-48de-8967-3b0213b055ec" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityRevenueRecognized_82c86391-3ff1-41ff-abb1-4d9c6f4620a8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerLiabilityRevenueRecognized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_ChangeInContractWithCustomerLiabilityRollForward_704f62e9-cd87-4514-bb75-12843224da52" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityRevenueRecognized_82c86391-3ff1-41ff-abb1-4d9c6f4620a8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_ContractwithCustomerLiabilityAdditions_92778a04-39bb-409f-a09c-ea1a4d0ae397" xlink:href="paa-20211231.xsd#paa_ContractwithCustomerLiabilityAdditions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_ChangeInContractWithCustomerLiabilityRollForward_704f62e9-cd87-4514-bb75-12843224da52" xlink:to="loc_paa_ContractwithCustomerLiabilityAdditions_92778a04-39bb-409f-a09c-ea1a4d0ae397" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiability_7b4f1d9e-5137-4fc2-9afb-420d293296e2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerLiability"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_ContractWithCustomerAssetAndLiabilityTable_ebd9fb57-8278-4d6b-8707-528fbdf0fe41" xlink:href="paa-20211231.xsd#paa_ContractWithCustomerAssetAndLiabilityTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_paa_ContractWithCustomerAssetAndLiabilityLineItems_40a1bcbd-d804-45d6-9a19-7a4ac83e8783" xlink:to="loc_paa_ContractWithCustomerAssetAndLiabilityTable_ebd9fb57-8278-4d6b-8707-528fbdf0fe41" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfArrangementAxis_79783a67-020c-496f-9bda-87b143071edf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TypeOfArrangementAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_paa_ContractWithCustomerAssetAndLiabilityTable_ebd9fb57-8278-4d6b-8707-528fbdf0fe41" xlink:to="loc_us-gaap_TypeOfArrangementAxis_79783a67-020c-496f-9bda-87b143071edf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_79783a67-020c-496f-9bda-87b143071edf_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TypeOfArrangementAxis_79783a67-020c-496f-9bda-87b143071edf" xlink:to="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_79783a67-020c-496f-9bda-87b143071edf_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_d2d3c63a-c654-4b36-aa2b-37df4c5feb69" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TypeOfArrangementAxis_79783a67-020c-496f-9bda-87b143071edf" xlink:to="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_d2d3c63a-c654-4b36-aa2b-37df4c5feb69" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_CrudeOilSalesAgreementsEnteredIntoInConjunctionWIthStorageArrangementsAndFutureInventoryExchangesMember_8a6eddbf-9f7b-4fc2-9e87-ba6f026ef99e" xlink:href="paa-20211231.xsd#paa_CrudeOilSalesAgreementsEnteredIntoInConjunctionWIthStorageArrangementsAndFutureInventoryExchangesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_d2d3c63a-c654-4b36-aa2b-37df4c5feb69" xlink:to="loc_paa_CrudeOilSalesAgreementsEnteredIntoInConjunctionWIthStorageArrangementsAndFutureInventoryExchangesMember_8a6eddbf-9f7b-4fc2-9e87-ba6f026ef99e" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/RevenuesandAccountsReceivablePerformanceObligationsDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#RevenuesandAccountsReceivablePerformanceObligationsDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/RevenuesandAccountsReceivablePerformanceObligationsDetails" xlink:type="extended" id="id0d58319727e44098298ead83541ccc8_RevenuesandAccountsReceivablePerformanceObligationsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_702d6fe7-144a-4305-bdc2-11e37338d8d7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligation_42d2296a-f716-405d-8c1c-5d6a1cd8c52c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_702d6fe7-144a-4305-bdc2-11e37338d8d7" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligation_42d2296a-f716-405d-8c1c-5d6a1cd8c52c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_561a84d0-8952-4225-aaf3-e21d8d3b2310" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_702d6fe7-144a-4305-bdc2-11e37338d8d7" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_561a84d0-8952-4225-aaf3-e21d8d3b2310" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_0bbc5245-4342-4e66-b252-4a709ff0ea53" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_702d6fe7-144a-4305-bdc2-11e37338d8d7" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_0bbc5245-4342-4e66-b252-4a709ff0ea53" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_0e28a8e4-ca66-424e-adac-248c607b007b" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_0bbc5245-4342-4e66-b252-4a709ff0ea53" xlink:to="loc_srt_ProductOrServiceAxis_0e28a8e4-ca66-424e-adac-248c607b007b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_0e28a8e4-ca66-424e-adac-248c607b007b_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_0e28a8e4-ca66-424e-adac-248c607b007b" xlink:to="loc_srt_ProductsAndServicesDomain_0e28a8e4-ca66-424e-adac-248c607b007b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_1cd92ae0-29ed-4717-8500-d2d32c9d797f" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_0e28a8e4-ca66-424e-adac-248c607b007b" xlink:to="loc_srt_ProductsAndServicesDomain_1cd92ae0-29ed-4717-8500-d2d32c9d797f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PipelineRevenuesSupportedByMinimumVolumeCommitmentsAndLongTermCapacityAgreementsMember_2f7fcc9d-d73c-44f5-9bbd-cb4051ba636d" xlink:href="paa-20211231.xsd#paa_PipelineRevenuesSupportedByMinimumVolumeCommitmentsAndLongTermCapacityAgreementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_1cd92ae0-29ed-4717-8500-d2d32c9d797f" xlink:to="loc_paa_PipelineRevenuesSupportedByMinimumVolumeCommitmentsAndLongTermCapacityAgreementsMember_2f7fcc9d-d73c-44f5-9bbd-cb4051ba636d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_TerminallingLongTermStorageAndThroughputAgreementsRevenuesMember_1fd81d0e-c033-4aba-a4e4-c0790a924dd1" xlink:href="paa-20211231.xsd#paa_TerminallingLongTermStorageAndThroughputAgreementsRevenuesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_1cd92ae0-29ed-4717-8500-d2d32c9d797f" xlink:to="loc_paa_TerminallingLongTermStorageAndThroughputAgreementsRevenuesMember_1fd81d0e-c033-4aba-a4e4-c0790a924dd1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis_3d1730d7-b37d-4d42-b3dd-cc65c01dd519" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_0bbc5245-4342-4e66-b252-4a709ff0ea53" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis_3d1730d7-b37d-4d42-b3dd-cc65c01dd519" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/RevenuesandAccountsReceivablePerformanceObligationsDetails_1" xlink:type="simple" xlink:href="paa-20211231.xsd#RevenuesandAccountsReceivablePerformanceObligationsDetails_1"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/RevenuesandAccountsReceivablePerformanceObligationsDetails_1" xlink:type="extended" id="iff4c29cb62d449689c9ce88648f6f05b_RevenuesandAccountsReceivablePerformanceObligationsDetails_1">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_702d6fe7-144a-4305-bdc2-11e37338d8d7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligation_42d2296a-f716-405d-8c1c-5d6a1cd8c52c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_702d6fe7-144a-4305-bdc2-11e37338d8d7" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligation_42d2296a-f716-405d-8c1c-5d6a1cd8c52c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_561a84d0-8952-4225-aaf3-e21d8d3b2310" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_702d6fe7-144a-4305-bdc2-11e37338d8d7" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_561a84d0-8952-4225-aaf3-e21d8d3b2310" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_0bbc5245-4342-4e66-b252-4a709ff0ea53" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_702d6fe7-144a-4305-bdc2-11e37338d8d7" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_0bbc5245-4342-4e66-b252-4a709ff0ea53" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_0e28a8e4-ca66-424e-adac-248c607b007b" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_0bbc5245-4342-4e66-b252-4a709ff0ea53" xlink:to="loc_srt_ProductOrServiceAxis_0e28a8e4-ca66-424e-adac-248c607b007b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_0e28a8e4-ca66-424e-adac-248c607b007b_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_0e28a8e4-ca66-424e-adac-248c607b007b" xlink:to="loc_srt_ProductsAndServicesDomain_0e28a8e4-ca66-424e-adac-248c607b007b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_1cd92ae0-29ed-4717-8500-d2d32c9d797f" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_0e28a8e4-ca66-424e-adac-248c607b007b" xlink:to="loc_srt_ProductsAndServicesDomain_1cd92ae0-29ed-4717-8500-d2d32c9d797f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PipelineRevenuesSupportedByMinimumVolumeCommitmentsAndLongTermCapacityAgreementsMember_2f7fcc9d-d73c-44f5-9bbd-cb4051ba636d" xlink:href="paa-20211231.xsd#paa_PipelineRevenuesSupportedByMinimumVolumeCommitmentsAndLongTermCapacityAgreementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_1cd92ae0-29ed-4717-8500-d2d32c9d797f" xlink:to="loc_paa_PipelineRevenuesSupportedByMinimumVolumeCommitmentsAndLongTermCapacityAgreementsMember_2f7fcc9d-d73c-44f5-9bbd-cb4051ba636d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_TerminallingLongTermStorageAndThroughputAgreementsRevenuesMember_1fd81d0e-c033-4aba-a4e4-c0790a924dd1" xlink:href="paa-20211231.xsd#paa_TerminallingLongTermStorageAndThroughputAgreementsRevenuesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_1cd92ae0-29ed-4717-8500-d2d32c9d797f" xlink:to="loc_paa_TerminallingLongTermStorageAndThroughputAgreementsRevenuesMember_1fd81d0e-c033-4aba-a4e4-c0790a924dd1" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/NetIncomeLossPerCommonUnitDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#NetIncomeLossPerCommonUnitDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/NetIncomeLossPerCommonUnitDetails" xlink:type="extended" id="i4c2e2fc820e74ebb87f63a4907b452f1_NetIncomeLossPerCommonUnitDetails">
    <link:loc xlink:type="locator" xlink:label="loc_paa_BasicAndDilutedNetIncomePerCommonUnitLineItems_7ee8d139-343a-4fd0-a7a8-62636c5642ae" xlink:href="paa-20211231.xsd#paa_BasicAndDilutedNetIncomePerCommonUnitLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_38186c2a-9cde-4d4b-ab96-14fa6ee3254c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_BasicAndDilutedNetIncomePerCommonUnitLineItems_7ee8d139-343a-4fd0-a7a8-62636c5642ae" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_38186c2a-9cde-4d4b-ab96-14fa6ee3254c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerLimitedPartnershipUnitAbstract_202a5c63-0621-43b0-bf1b-6ad2852d5375" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EarningsPerLimitedPartnershipUnitAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_BasicAndDilutedNetIncomePerCommonUnitLineItems_7ee8d139-343a-4fd0-a7a8-62636c5642ae" xlink:to="loc_us-gaap_EarningsPerLimitedPartnershipUnitAbstract_202a5c63-0621-43b0-bf1b-6ad2852d5375" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_7c53c3ee-5678-4482-8f1f-cb7e9f5adbbf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerLimitedPartnershipUnitAbstract_202a5c63-0621-43b0-bf1b-6ad2852d5375" xlink:to="loc_us-gaap_NetIncomeLoss_7c53c3ee-5678-4482-8f1f-cb7e9f5adbbf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockDividendsIncomeStatementImpact_cb7ee452-8d99-4414-97d8-c8a08761e165" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PreferredStockDividendsIncomeStatementImpact"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerLimitedPartnershipUnitAbstract_202a5c63-0621-43b0-bf1b-6ad2852d5375" xlink:to="loc_us-gaap_PreferredStockDividendsIncomeStatementImpact_cb7ee452-8d99-4414-97d8-c8a08761e165" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ParticipatingSecuritiesDistributedAndUndistributedEarningsLossBasic_9eb60662-7dd1-4247-a8a0-318fa705ff51" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ParticipatingSecuritiesDistributedAndUndistributedEarningsLossBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerLimitedPartnershipUnitAbstract_202a5c63-0621-43b0-bf1b-6ad2852d5375" xlink:to="loc_us-gaap_ParticipatingSecuritiesDistributedAndUndistributedEarningsLossBasic_9eb60662-7dd1-4247-a8a0-318fa705ff51" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_OtherAllocatedEarningsBasic_48b97c3b-d660-4de5-8a30-316a80c2693e" xlink:href="paa-20211231.xsd#paa_OtherAllocatedEarningsBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerLimitedPartnershipUnitAbstract_202a5c63-0621-43b0-bf1b-6ad2852d5375" xlink:to="loc_paa_OtherAllocatedEarningsBasic_48b97c3b-d660-4de5-8a30-316a80c2693e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_NetIncomeLossAllocatedtoCommonUnitholdersBasic_d5ff0225-ec1c-47d2-808c-e3a10bfd7710" xlink:href="paa-20211231.xsd#paa_NetIncomeLossAllocatedtoCommonUnitholdersBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerLimitedPartnershipUnitAbstract_202a5c63-0621-43b0-bf1b-6ad2852d5375" xlink:to="loc_paa_NetIncomeLossAllocatedtoCommonUnitholdersBasic_d5ff0225-ec1c-47d2-808c-e3a10bfd7710" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageLimitedPartnershipUnitsOutstanding_5c25032d-a0e3-4e95-ad3f-feff123f9651" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_WeightedAverageLimitedPartnershipUnitsOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerLimitedPartnershipUnitAbstract_202a5c63-0621-43b0-bf1b-6ad2852d5375" xlink:to="loc_us-gaap_WeightedAverageLimitedPartnershipUnitsOutstanding_5c25032d-a0e3-4e95-ad3f-feff123f9651" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossPerOutstandingLimitedPartnershipUnitBasicNetOfTax_c45862e3-37b3-4d87-b9b9-d0b34e284b9f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLossPerOutstandingLimitedPartnershipUnitBasicNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerLimitedPartnershipUnitAbstract_202a5c63-0621-43b0-bf1b-6ad2852d5375" xlink:to="loc_us-gaap_NetIncomeLossPerOutstandingLimitedPartnershipUnitBasicNetOfTax_c45862e3-37b3-4d87-b9b9-d0b34e284b9f" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossPerOutstandingLimitedPartnershipUnitDilutedAbstract_8886ebf1-0dd8-4366-81df-e3905154b4fc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLossPerOutstandingLimitedPartnershipUnitDilutedAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_BasicAndDilutedNetIncomePerCommonUnitLineItems_7ee8d139-343a-4fd0-a7a8-62636c5642ae" xlink:to="loc_us-gaap_NetIncomeLossPerOutstandingLimitedPartnershipUnitDilutedAbstract_8886ebf1-0dd8-4366-81df-e3905154b4fc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_21f98882-4016-43a9-a9be-77f2263d2ab0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLoss"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PreferredStockDividendsIncomeStatementImpactDiluted_c00d500e-c603-4440-9ee1-98ff010cb2a4" xlink:href="paa-20211231.xsd#paa_PreferredStockDividendsIncomeStatementImpactDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetIncomeLossPerOutstandingLimitedPartnershipUnitDilutedAbstract_8886ebf1-0dd8-4366-81df-e3905154b4fc" xlink:to="loc_paa_PreferredStockDividendsIncomeStatementImpactDiluted_c00d500e-c603-4440-9ee1-98ff010cb2a4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ParticipatingSecuritiesDistributedAndUndistributedEarningsLossBasic_b6a05600-23c3-4a55-806d-cb2f5e089240" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ParticipatingSecuritiesDistributedAndUndistributedEarningsLossBasic"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_NetIncomeLossAllocatedtoCommonUnitholdersDiluted_8c8c3d6d-1154-416b-82f0-a361fc70c1dc" xlink:href="paa-20211231.xsd#paa_NetIncomeLossAllocatedtoCommonUnitholdersDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetIncomeLossPerOutstandingLimitedPartnershipUnitDilutedAbstract_8886ebf1-0dd8-4366-81df-e3905154b4fc" xlink:to="loc_paa_NetIncomeLossAllocatedtoCommonUnitholdersDiluted_8c8c3d6d-1154-416b-82f0-a361fc70c1dc" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageLimitedPartnershipUnitsOutstanding_35c1e48e-cd6f-4b20-8729-8d2c7179f9fc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_WeightedAverageLimitedPartnershipUnitsOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustmentAbstract_f89a5c72-9350-4c2a-9eef-18bb350c3f6d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustmentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetIncomeLossPerOutstandingLimitedPartnershipUnitDilutedAbstract_8886ebf1-0dd8-4366-81df-e3905154b4fc" xlink:to="loc_us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustmentAbstract_f89a5c72-9350-4c2a-9eef-18bb350c3f6d" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_WeightedAverageNumberDilutedLimitedPartnershipUnitsOutstandingAdjustmentSeriesAPreferredUnits_ec2cb8c6-5adc-40cd-ae6a-4b2f69044247" xlink:href="paa-20211231.xsd#paa_WeightedAverageNumberDilutedLimitedPartnershipUnitsOutstandingAdjustmentSeriesAPreferredUnits"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustmentAbstract_f89a5c72-9350-4c2a-9eef-18bb350c3f6d" xlink:to="loc_paa_WeightedAverageNumberDilutedLimitedPartnershipUnitsOutstandingAdjustmentSeriesAPreferredUnits_ec2cb8c6-5adc-40cd-ae6a-4b2f69044247" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumerDilutedLimitedPartnershipUnitsOutstandingAdjustment_cefdace7-6d7d-4563-b80d-6897634d2434" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_WeightedAverageNumerDilutedLimitedPartnershipUnitsOutstandingAdjustment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustmentAbstract_f89a5c72-9350-4c2a-9eef-18bb350c3f6d" xlink:to="loc_us-gaap_WeightedAverageNumerDilutedLimitedPartnershipUnitsOutstandingAdjustment_cefdace7-6d7d-4563-b80d-6897634d2434" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageLimitedPartnershipUnitsOutstandingDiluted_0aa19c25-43d7-4f5d-8f98-c2abeee1f230" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_WeightedAverageLimitedPartnershipUnitsOutstandingDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetIncomeLossPerOutstandingLimitedPartnershipUnitDilutedAbstract_8886ebf1-0dd8-4366-81df-e3905154b4fc" xlink:to="loc_us-gaap_WeightedAverageLimitedPartnershipUnitsOutstandingDiluted_0aa19c25-43d7-4f5d-8f98-c2abeee1f230" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossNetOfTaxPerOutstandingLimitedPartnershipUnitDiluted_9ccc3f40-ad13-46bb-b599-7097d54bf0f0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLossNetOfTaxPerOutstandingLimitedPartnershipUnitDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetIncomeLossPerOutstandingLimitedPartnershipUnitDilutedAbstract_8886ebf1-0dd8-4366-81df-e3905154b4fc" xlink:to="loc_us-gaap_NetIncomeLossNetOfTaxPerOutstandingLimitedPartnershipUnitDiluted_9ccc3f40-ad13-46bb-b599-7097d54bf0f0" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_ScheduleOfCalculationOfBasicAndDilutedNetIncomePerCommonUnitTable_a4d32add-bc5d-457f-b256-4b56d88d2376" xlink:href="paa-20211231.xsd#paa_ScheduleOfCalculationOfBasicAndDilutedNetIncomePerCommonUnitTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_paa_BasicAndDilutedNetIncomePerCommonUnitLineItems_7ee8d139-343a-4fd0-a7a8-62636c5642ae" xlink:to="loc_paa_ScheduleOfCalculationOfBasicAndDilutedNetIncomePerCommonUnitTable_a4d32add-bc5d-457f-b256-4b56d88d2376" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_1e4e0bd3-5f33-405e-9bba-74cf86216004" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountByClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_paa_ScheduleOfCalculationOfBasicAndDilutedNetIncomePerCommonUnitTable_a4d32add-bc5d-457f-b256-4b56d88d2376" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_1e4e0bd3-5f33-405e-9bba-74cf86216004" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_1e4e0bd3-5f33-405e-9bba-74cf86216004_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_1e4e0bd3-5f33-405e-9bba-74cf86216004" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_1e4e0bd3-5f33-405e-9bba-74cf86216004_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_3fc016cc-d956-4fba-b681-fd767d5d65d6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_1e4e0bd3-5f33-405e-9bba-74cf86216004" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_3fc016cc-d956-4fba-b681-fd767d5d65d6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SeriesAPreferredUnitsMember_c9b08443-fbaa-4562-9a7f-b117245fcfc3" xlink:href="paa-20211231.xsd#paa_SeriesAPreferredUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_3fc016cc-d956-4fba-b681-fd767d5d65d6" xlink:to="loc_paa_SeriesAPreferredUnitsMember_c9b08443-fbaa-4562-9a7f-b117245fcfc3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SeriesBPreferredUnitsMember_db41fcb2-9c90-430b-9ebb-ba9b5d957eae" xlink:href="paa-20211231.xsd#paa_SeriesBPreferredUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_3fc016cc-d956-4fba-b681-fd767d5d65d6" xlink:to="loc_paa_SeriesBPreferredUnitsMember_db41fcb2-9c90-430b-9ebb-ba9b5d957eae" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_CommonUnitsMember_33bc338c-0f56-4f47-b701-269bd95cf30e" xlink:href="paa-20211231.xsd#paa_CommonUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_3fc016cc-d956-4fba-b681-fd767d5d65d6" xlink:to="loc_paa_CommonUnitsMember_33bc338c-0f56-4f47-b701-269bd95cf30e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_16bd3fbe-0e5f-4170-ac5e-6c23d4d40250" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_paa_ScheduleOfCalculationOfBasicAndDilutedNetIncomePerCommonUnitTable_a4d32add-bc5d-457f-b256-4b56d88d2376" xlink:to="loc_us-gaap_AwardTypeAxis_16bd3fbe-0e5f-4170-ac5e-6c23d4d40250" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_16bd3fbe-0e5f-4170-ac5e-6c23d4d40250_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_16bd3fbe-0e5f-4170-ac5e-6c23d4d40250" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_16bd3fbe-0e5f-4170-ac5e-6c23d4d40250_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_343861b1-e974-4089-9569-97f719be294d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_16bd3fbe-0e5f-4170-ac5e-6c23d4d40250" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_343861b1-e974-4089-9569-97f719be294d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_EquityIndexedCompensationPlanAwardMember_70e79188-45de-4cdd-a90e-763d99d25262" xlink:href="paa-20211231.xsd#paa_EquityIndexedCompensationPlanAwardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_343861b1-e974-4089-9569-97f719be294d" xlink:to="loc_paa_EquityIndexedCompensationPlanAwardMember_70e79188-45de-4cdd-a90e-763d99d25262" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_bec7bd37-4341-46d2-87c3-c15d95de4f4a" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_paa_ScheduleOfCalculationOfBasicAndDilutedNetIncomePerCommonUnitTable_a4d32add-bc5d-457f-b256-4b56d88d2376" xlink:to="loc_srt_RangeAxis_bec7bd37-4341-46d2-87c3-c15d95de4f4a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_bec7bd37-4341-46d2-87c3-c15d95de4f4a_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_bec7bd37-4341-46d2-87c3-c15d95de4f4a" xlink:to="loc_srt_RangeMember_bec7bd37-4341-46d2-87c3-c15d95de4f4a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_573803cd-724c-423e-a05a-51f45ca43c7d" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_bec7bd37-4341-46d2-87c3-c15d95de4f4a" xlink:to="loc_srt_RangeMember_573803cd-724c-423e-a05a-51f45ca43c7d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_WeightedAverageMember_4629eb23-a890-4173-a78f-83cc2983d4c4" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_WeightedAverageMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_573803cd-724c-423e-a05a-51f45ca43c7d" xlink:to="loc_srt_WeightedAverageMember_4629eb23-a890-4173-a78f-83cc2983d4c4" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/InventoryLinefillandBaseGasandLongtermInventoryDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#InventoryLinefillandBaseGasandLongtermInventoryDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/InventoryLinefillandBaseGasandLongtermInventoryDetails" xlink:type="extended" id="ia0be640c6a924ec38adfcfb3ce251994_InventoryLinefillandBaseGasandLongtermInventoryDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryLineItems_7465d54f-cc38-423a-8480-b013fd22e25b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InventoryLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryAdjustmentsAbstract_f5f2960c-579f-4b2b-ae06-ae7b2acb6ab6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InventoryAdjustmentsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InventoryLineItems_7465d54f-cc38-423a-8480-b013fd22e25b" xlink:to="loc_us-gaap_InventoryAdjustmentsAbstract_f5f2960c-579f-4b2b-ae06-ae7b2acb6ab6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryWriteDown_77724331-0f63-43c1-9d5c-9854c6c1ab0e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InventoryWriteDown"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InventoryAdjustmentsAbstract_f5f2960c-579f-4b2b-ae06-ae7b2acb6ab6" xlink:to="loc_us-gaap_InventoryWriteDown_77724331-0f63-43c1-9d5c-9854c6c1ab0e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_InventoryWriteDownNoncurrent_28714d94-c09d-4f81-9f55-2fb626c5658b" xlink:href="paa-20211231.xsd#paa_InventoryWriteDownNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InventoryAdjustmentsAbstract_f5f2960c-579f-4b2b-ae06-ae7b2acb6ab6" xlink:to="loc_paa_InventoryWriteDownNoncurrent_28714d94-c09d-4f81-9f55-2fb626c5658b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryDisclosureAbstract_80eca2d8-a7c6-4bc0-baaa-8598685c1eb4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InventoryDisclosureAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InventoryLineItems_7465d54f-cc38-423a-8480-b013fd22e25b" xlink:to="loc_us-gaap_InventoryDisclosureAbstract_80eca2d8-a7c6-4bc0-baaa-8598685c1eb4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_InventoryVolumesCurrent_c67e9a50-b606-4dce-8319-48d017cd2b9f" xlink:href="paa-20211231.xsd#paa_InventoryVolumesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InventoryDisclosureAbstract_80eca2d8-a7c6-4bc0-baaa-8598685c1eb4" xlink:to="loc_paa_InventoryVolumesCurrent_c67e9a50-b606-4dce-8319-48d017cd2b9f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_InventoryVolumesLinefillAndBaseGas_c241cd42-c243-4c15-a406-a10b1ae9b1ea" xlink:href="paa-20211231.xsd#paa_InventoryVolumesLinefillAndBaseGas"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InventoryDisclosureAbstract_80eca2d8-a7c6-4bc0-baaa-8598685c1eb4" xlink:to="loc_paa_InventoryVolumesLinefillAndBaseGas_c241cd42-c243-4c15-a406-a10b1ae9b1ea" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_InventoryVolumesNoncurrent_a01a2ac8-adfe-43c7-b991-16250efac318" xlink:href="paa-20211231.xsd#paa_InventoryVolumesNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InventoryDisclosureAbstract_80eca2d8-a7c6-4bc0-baaa-8598685c1eb4" xlink:to="loc_paa_InventoryVolumesNoncurrent_a01a2ac8-adfe-43c7-b991-16250efac318" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryNet_d21f4742-b5bd-4cad-ba83-3bcddbe49d66" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InventoryNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InventoryDisclosureAbstract_80eca2d8-a7c6-4bc0-baaa-8598685c1eb4" xlink:to="loc_us-gaap_InventoryNet_d21f4742-b5bd-4cad-ba83-3bcddbe49d66" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_LinefillAndBaseGas_0a4d8a40-bd4e-4a23-9198-44820e44df66" xlink:href="paa-20211231.xsd#paa_LinefillAndBaseGas"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InventoryDisclosureAbstract_80eca2d8-a7c6-4bc0-baaa-8598685c1eb4" xlink:to="loc_paa_LinefillAndBaseGas_0a4d8a40-bd4e-4a23-9198-44820e44df66" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryNoncurrent_8e761581-fdbe-4bb6-b7d1-2df1b6490939" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InventoryNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InventoryDisclosureAbstract_80eca2d8-a7c6-4bc0-baaa-8598685c1eb4" xlink:to="loc_us-gaap_InventoryNoncurrent_8e761581-fdbe-4bb6-b7d1-2df1b6490939" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_InventoryCurrentAndNoncurrent_939db68a-b75d-4be4-946d-606f7b46cd90" xlink:href="paa-20211231.xsd#paa_InventoryCurrentAndNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InventoryDisclosureAbstract_80eca2d8-a7c6-4bc0-baaa-8598685c1eb4" xlink:to="loc_paa_InventoryCurrentAndNoncurrent_939db68a-b75d-4be4-946d-606f7b46cd90" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_InventoryWeightedAveragePricePerUnitCurrent_55ff8153-0bce-4951-ab74-7f1ed0747f81" xlink:href="paa-20211231.xsd#paa_InventoryWeightedAveragePricePerUnitCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InventoryDisclosureAbstract_80eca2d8-a7c6-4bc0-baaa-8598685c1eb4" xlink:to="loc_paa_InventoryWeightedAveragePricePerUnitCurrent_55ff8153-0bce-4951-ab74-7f1ed0747f81" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_InventoryWeightedAveragePricePerUnitLinefillAndBaseGas_d40313ed-b8ff-455e-8458-d5a42c092aa8" xlink:href="paa-20211231.xsd#paa_InventoryWeightedAveragePricePerUnitLinefillAndBaseGas"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InventoryDisclosureAbstract_80eca2d8-a7c6-4bc0-baaa-8598685c1eb4" xlink:to="loc_paa_InventoryWeightedAveragePricePerUnitLinefillAndBaseGas_d40313ed-b8ff-455e-8458-d5a42c092aa8" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_InventoryWeightedAveragePricePerUnitNoncurrent_36ec34e0-199a-4115-a1f2-9c5663c13227" xlink:href="paa-20211231.xsd#paa_InventoryWeightedAveragePricePerUnitNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InventoryDisclosureAbstract_80eca2d8-a7c6-4bc0-baaa-8598685c1eb4" xlink:to="loc_paa_InventoryWeightedAveragePricePerUnitNoncurrent_36ec34e0-199a-4115-a1f2-9c5663c13227" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryCurrentTable_cdc71786-c57a-432f-9296-353ac219f889" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InventoryCurrentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_InventoryLineItems_7465d54f-cc38-423a-8480-b013fd22e25b" xlink:to="loc_us-gaap_InventoryCurrentTable_cdc71786-c57a-432f-9296-353ac219f889" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesInventoryAxis_baa6f12e-4eb5-42eb-a01d-c7dd3a62a966" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesInventoryAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_InventoryCurrentTable_cdc71786-c57a-432f-9296-353ac219f889" xlink:to="loc_us-gaap_PublicUtilitiesInventoryAxis_baa6f12e-4eb5-42eb-a01d-c7dd3a62a966" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesInventoryTypeDomain_baa6f12e-4eb5-42eb-a01d-c7dd3a62a966_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesInventoryTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PublicUtilitiesInventoryAxis_baa6f12e-4eb5-42eb-a01d-c7dd3a62a966" xlink:to="loc_us-gaap_PublicUtilitiesInventoryTypeDomain_baa6f12e-4eb5-42eb-a01d-c7dd3a62a966_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesInventoryTypeDomain_b9b42fa4-98d9-4a83-b098-0ada8a2a4764" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesInventoryTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PublicUtilitiesInventoryAxis_baa6f12e-4eb5-42eb-a01d-c7dd3a62a966" xlink:to="loc_us-gaap_PublicUtilitiesInventoryTypeDomain_b9b42fa4-98d9-4a83-b098-0ada8a2a4764" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CrudeOilMember_adc63f7c-2f62-4095-ad27-47a105e337b1" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CrudeOilMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesInventoryTypeDomain_b9b42fa4-98d9-4a83-b098-0ada8a2a4764" xlink:to="loc_srt_CrudeOilMember_adc63f7c-2f62-4095-ad27-47a105e337b1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NaturalGasLiquidsReservesMember_34292967-39be-4507-95d1-1d4e474bfaef" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_NaturalGasLiquidsReservesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesInventoryTypeDomain_b9b42fa4-98d9-4a83-b098-0ada8a2a4764" xlink:to="loc_srt_NaturalGasLiquidsReservesMember_34292967-39be-4507-95d1-1d4e474bfaef" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NaturalGasReservesMember_4bebedce-b56b-4bb9-9570-e1c19a296917" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_NaturalGasReservesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesInventoryTypeDomain_b9b42fa4-98d9-4a83-b098-0ada8a2a4764" xlink:to="loc_srt_NaturalGasReservesMember_4bebedce-b56b-4bb9-9570-e1c19a296917" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_OtherInventoryMember_4bb8b852-6735-44f6-9e08-f7fd2ddd2da8" xlink:href="paa-20211231.xsd#paa_OtherInventoryMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesInventoryTypeDomain_b9b42fa4-98d9-4a83-b098-0ada8a2a4764" xlink:to="loc_paa_OtherInventoryMember_4bb8b852-6735-44f6-9e08-f7fd2ddd2da8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationAxis_56ffbabc-a64a-41ab-8b1b-cfc817389108" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisposalGroupClassificationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_InventoryCurrentTable_cdc71786-c57a-432f-9296-353ac219f889" xlink:to="loc_us-gaap_DisposalGroupClassificationAxis_56ffbabc-a64a-41ab-8b1b-cfc817389108" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_56ffbabc-a64a-41ab-8b1b-cfc817389108_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisposalGroupClassificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_56ffbabc-a64a-41ab-8b1b-cfc817389108" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_56ffbabc-a64a-41ab-8b1b-cfc817389108_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_0b0738b3-4d1b-40d7-a460-e87ca42729dd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisposalGroupClassificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_56ffbabc-a64a-41ab-8b1b-cfc817389108" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_0b0738b3-4d1b-40d7-a460-e87ca42729dd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember_af319775-04e6-48a6-8a23-c2a944c42825" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupClassificationDomain_0b0738b3-4d1b-40d7-a460-e87ca42729dd" xlink:to="loc_us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember_af319775-04e6-48a6-8a23-c2a944c42825" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_6b427736-6689-4781-a878-9c7bde7a2183" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_InventoryCurrentTable_cdc71786-c57a-432f-9296-353ac219f889" xlink:to="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_6b427736-6689-4781-a878-9c7bde7a2183" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_6b427736-6689-4781-a878-9c7bde7a2183_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_6b427736-6689-4781-a878-9c7bde7a2183" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_6b427736-6689-4781-a878-9c7bde7a2183_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_7bced81a-a376-4b12-9bcc-f9f47c1f1cb9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_6b427736-6689-4781-a878-9c7bde7a2183" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_7bced81a-a376-4b12-9bcc-f9f47c1f1cb9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PinePrairieAndSouthernPinesNaturalGasStorageFacilitiesMember_5302e727-fe15-425a-b646-213948ffb410" xlink:href="paa-20211231.xsd#paa_PinePrairieAndSouthernPinesNaturalGasStorageFacilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_7bced81a-a376-4b12-9bcc-f9f47c1f1cb9" xlink:to="loc_paa_PinePrairieAndSouthernPinesNaturalGasStorageFacilitiesMember_5302e727-fe15-425a-b646-213948ffb410" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/PropertyandEquipmentDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#PropertyandEquipmentDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/PropertyandEquipmentDetails" xlink:type="extended" id="id72f72ea408f488eb86c9ff34a4280fb_PropertyandEquipmentDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_1f9b0eb8-932f-4a07-979f-6bb4835f2b9a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestCostsCapitalized_abe68d37-b845-43a6-b9f8-e1563b5e587e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestCostsCapitalized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_1f9b0eb8-932f-4a07-979f-6bb4835f2b9a" xlink:to="loc_us-gaap_InterestCostsCapitalized_abe68d37-b845-43a6-b9f8-e1563b5e587e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_ad6c3e82-85c0-443e-bb9d-e5b6252f621d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_1f9b0eb8-932f-4a07-979f-6bb4835f2b9a" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_ad6c3e82-85c0-443e-bb9d-e5b6252f621d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetBeforeAccumulatedDepreciationAndAmortization_43e800cc-3d04-44a2-84bd-160a67cb0a54" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetBeforeAccumulatedDepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_1f9b0eb8-932f-4a07-979f-6bb4835f2b9a" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetBeforeAccumulatedDepreciationAndAmortization_43e800cc-3d04-44a2-84bd-160a67cb0a54" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAccumulatedDepreciationAndAmortization_05264701-21c4-4eb9-a343-f9026663c191" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAccumulatedDepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_1f9b0eb8-932f-4a07-979f-6bb4835f2b9a" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAccumulatedDepreciationAndAmortization_05264701-21c4-4eb9-a343-f9026663c191" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization_9f01de26-2fe7-4e45-8ae5-dc26604d1b6e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_1f9b0eb8-932f-4a07-979f-6bb4835f2b9a" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization_9f01de26-2fe7-4e45-8ae5-dc26604d1b6e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Depreciation_111f21f9-5314-4086-a9fa-05858afa5104" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Depreciation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_1f9b0eb8-932f-4a07-979f-6bb4835f2b9a" xlink:to="loc_us-gaap_Depreciation_111f21f9-5314-4086-a9fa-05858afa5104" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossPerOutstandingLimitedPartnershipUnitBasicNetOfTax_2801d194-e17e-4d62-9c57-eecf6095c7d9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLossPerOutstandingLimitedPartnershipUnitBasicNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_1f9b0eb8-932f-4a07-979f-6bb4835f2b9a" xlink:to="loc_us-gaap_NetIncomeLossPerOutstandingLimitedPartnershipUnitBasicNetOfTax_2801d194-e17e-4d62-9c57-eecf6095c7d9" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossNetOfTaxPerOutstandingLimitedPartnershipUnitDiluted_fc149270-38a6-4e27-aef8-15160430d081" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLossNetOfTaxPerOutstandingLimitedPartnershipUnitDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_1f9b0eb8-932f-4a07-979f-6bb4835f2b9a" xlink:to="loc_us-gaap_NetIncomeLossNetOfTaxPerOutstandingLimitedPartnershipUnitDiluted_fc149270-38a6-4e27-aef8-15160430d081" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionInProgressExpendituresIncurredButNotYetPaid_f1e94f87-62a9-47e3-90a6-db67a6780fe3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConstructionInProgressExpendituresIncurredButNotYetPaid"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_1f9b0eb8-932f-4a07-979f-6bb4835f2b9a" xlink:to="loc_us-gaap_ConstructionInProgressExpendituresIncurredButNotYetPaid_f1e94f87-62a9-47e3-90a6-db67a6780fe3" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairmentOfLongLivedAssetsHeldForUse_6ac14ed8-f82b-4b00-be18-5904b3ffa87a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ImpairmentOfLongLivedAssetsHeldForUse"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_1f9b0eb8-932f-4a07-979f-6bb4835f2b9a" xlink:to="loc_us-gaap_ImpairmentOfLongLivedAssetsHeldForUse_6ac14ed8-f82b-4b00-be18-5904b3ffa87a" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_ImpairmentAnalysisCostOfCapitalTheoreticalMarketParticipant_8d68989d-f118-4f12-94ed-4176e6c8534a" xlink:href="paa-20211231.xsd#paa_ImpairmentAnalysisCostOfCapitalTheoreticalMarketParticipant"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_1f9b0eb8-932f-4a07-979f-6bb4835f2b9a" xlink:to="loc_paa_ImpairmentAnalysisCostOfCapitalTheoreticalMarketParticipant_8d68989d-f118-4f12-94ed-4176e6c8534a" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_80bf04fb-9b50-4450-94f0-b0dff1e20746" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_1f9b0eb8-932f-4a07-979f-6bb4835f2b9a" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_80bf04fb-9b50-4450-94f0-b0dff1e20746" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_34ec1a16-d872-45fe-831c-84386f20ead3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_80bf04fb-9b50-4450-94f0-b0dff1e20746" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_34ec1a16-d872-45fe-831c-84386f20ead3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_34ec1a16-d872-45fe-831c-84386f20ead3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_34ec1a16-d872-45fe-831c-84386f20ead3" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_34ec1a16-d872-45fe-831c-84386f20ead3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_eaeaba52-7c41-49e0-bd93-2f606ef8758c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_34ec1a16-d872-45fe-831c-84386f20ead3" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_eaeaba52-7c41-49e0-bd93-2f606ef8758c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentMember_cc9efefe-1f0e-40fe-b2d5-723f5dd00639" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_eaeaba52-7c41-49e0-bd93-2f606ef8758c" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentMember_cc9efefe-1f0e-40fe-b2d5-723f5dd00639" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_5103ad09-632f-43b3-96da-4232b25cb624" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_80bf04fb-9b50-4450-94f0-b0dff1e20746" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_5103ad09-632f-43b3-96da-4232b25cb624" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_5103ad09-632f-43b3-96da-4232b25cb624_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_5103ad09-632f-43b3-96da-4232b25cb624" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_5103ad09-632f-43b3-96da-4232b25cb624_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_3b531dce-acf0-4143-89cb-39dc0ec73dca" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_5103ad09-632f-43b3-96da-4232b25cb624" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_3b531dce-acf0-4143-89cb-39dc0ec73dca" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PipelinesMember_4a8144b0-549b-41ed-af22-d20ebbf9dc7b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PipelinesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_3b531dce-acf0-4143-89cb-39dc0ec73dca" xlink:to="loc_us-gaap_PipelinesMember_4a8144b0-549b-41ed-af22-d20ebbf9dc7b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_StorageTerminalAndRailFacilitiesMember_d152c318-5bac-4d51-b343-9f548d7f519f" xlink:href="paa-20211231.xsd#paa_StorageTerminalAndRailFacilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_3b531dce-acf0-4143-89cb-39dc0ec73dca" xlink:to="loc_paa_StorageTerminalAndRailFacilitiesMember_d152c318-5bac-4d51-b343-9f548d7f519f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_TruckingEquipmentAndOtherMember_5b4a55d3-f061-44b3-b6cb-7233a7dbfd79" xlink:href="paa-20211231.xsd#paa_TruckingEquipmentAndOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_3b531dce-acf0-4143-89cb-39dc0ec73dca" xlink:to="loc_paa_TruckingEquipmentAndOtherMember_5b4a55d3-f061-44b3-b6cb-7233a7dbfd79" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionInProgressMember_6ef2a0bb-ea13-4d46-9b31-a73948ba7ce2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConstructionInProgressMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_3b531dce-acf0-4143-89cb-39dc0ec73dca" xlink:to="loc_us-gaap_ConstructionInProgressMember_6ef2a0bb-ea13-4d46-9b31-a73948ba7ce2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OfficeEquipmentMember_bd4f33fb-f9e6-4faa-bae2-d6407b614034" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OfficeEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_3b531dce-acf0-4143-89cb-39dc0ec73dca" xlink:to="loc_us-gaap_OfficeEquipmentMember_bd4f33fb-f9e6-4faa-bae2-d6407b614034" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_LandAndOtherMember_9d0c6a24-e85b-4bd3-b7e3-48944f338b17" xlink:href="paa-20211231.xsd#paa_LandAndOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_3b531dce-acf0-4143-89cb-39dc0ec73dca" xlink:to="loc_paa_LandAndOtherMember_9d0c6a24-e85b-4bd3-b7e3-48944f338b17" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PipelineAndRelatedFacilitiesAndStorageTerminalAndRailFacilitiesMember_e6e9f5fc-d63b-4b5d-9db9-1956e30411ba" xlink:href="paa-20211231.xsd#paa_PipelineAndRelatedFacilitiesAndStorageTerminalAndRailFacilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_3b531dce-acf0-4143-89cb-39dc0ec73dca" xlink:to="loc_paa_PipelineAndRelatedFacilitiesAndStorageTerminalAndRailFacilitiesMember_e6e9f5fc-d63b-4b5d-9db9-1956e30411ba" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_0e806f5e-8df8-4d16-afbc-ee80d51d9be2" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_80bf04fb-9b50-4450-94f0-b0dff1e20746" xlink:to="loc_srt_RangeAxis_0e806f5e-8df8-4d16-afbc-ee80d51d9be2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_0e806f5e-8df8-4d16-afbc-ee80d51d9be2_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_0e806f5e-8df8-4d16-afbc-ee80d51d9be2" xlink:to="loc_srt_RangeMember_0e806f5e-8df8-4d16-afbc-ee80d51d9be2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_2e8ab1e3-4570-4186-b68b-cbc6924b4c1f" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_0e806f5e-8df8-4d16-afbc-ee80d51d9be2" xlink:to="loc_srt_RangeMember_2e8ab1e3-4570-4186-b68b-cbc6924b4c1f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_53c45984-86ec-4630-b852-cc0c4d2ded72" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_2e8ab1e3-4570-4186-b68b-cbc6924b4c1f" xlink:to="loc_srt_MinimumMember_53c45984-86ec-4630-b852-cc0c4d2ded72" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_b5aacf8d-1ac5-4e02-ad03-1917aaea70c9" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_2e8ab1e3-4570-4186-b68b-cbc6924b4c1f" xlink:to="loc_srt_MaximumMember_b5aacf8d-1ac5-4e02-ad03-1917aaea70c9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_a9ce9030-943d-4661-bc84-0aeba66939d9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountByClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_80bf04fb-9b50-4450-94f0-b0dff1e20746" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_a9ce9030-943d-4661-bc84-0aeba66939d9" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_a9ce9030-943d-4661-bc84-0aeba66939d9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_a9ce9030-943d-4661-bc84-0aeba66939d9" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_a9ce9030-943d-4661-bc84-0aeba66939d9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_5c3d76b9-e3a0-4b6d-8e7f-f81894f487a2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_a9ce9030-943d-4661-bc84-0aeba66939d9" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_5c3d76b9-e3a0-4b6d-8e7f-f81894f487a2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_CommonUnitsMember_8ff0102e-d919-4188-8421-bf6c393dfd47" xlink:href="paa-20211231.xsd#paa_CommonUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_5c3d76b9-e3a0-4b6d-8e7f-f81894f487a2" xlink:to="loc_paa_CommonUnitsMember_8ff0102e-d919-4188-8421-bf6c393dfd47" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ChangeInAccountingEstimateByTypeAxis_afbfd945-99fb-4881-997a-abf5bc67cf0e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ChangeInAccountingEstimateByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_80bf04fb-9b50-4450-94f0-b0dff1e20746" xlink:to="loc_us-gaap_ChangeInAccountingEstimateByTypeAxis_afbfd945-99fb-4881-997a-abf5bc67cf0e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ChangeInAccountingEstimateTypeDomain_afbfd945-99fb-4881-997a-abf5bc67cf0e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ChangeInAccountingEstimateTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ChangeInAccountingEstimateByTypeAxis_afbfd945-99fb-4881-997a-abf5bc67cf0e" xlink:to="loc_us-gaap_ChangeInAccountingEstimateTypeDomain_afbfd945-99fb-4881-997a-abf5bc67cf0e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ChangeInAccountingEstimateTypeDomain_118c2c05-058e-4c6b-a4eb-200d5f4ef729" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ChangeInAccountingEstimateTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ChangeInAccountingEstimateByTypeAxis_afbfd945-99fb-4881-997a-abf5bc67cf0e" xlink:to="loc_us-gaap_ChangeInAccountingEstimateTypeDomain_118c2c05-058e-4c6b-a4eb-200d5f4ef729" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ServiceLifeMember_e8ed8049-0022-47d8-ba4d-4e03a06bd0d2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ServiceLifeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ChangeInAccountingEstimateTypeDomain_118c2c05-058e-4c6b-a4eb-200d5f4ef729" xlink:to="loc_us-gaap_ServiceLifeMember_e8ed8049-0022-47d8-ba4d-4e03a06bd0d2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_425647c9-d913-492c-9e3e-4ff75b8db549" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_80bf04fb-9b50-4450-94f0-b0dff1e20746" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_425647c9-d913-492c-9e3e-4ff75b8db549" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_425647c9-d913-492c-9e3e-4ff75b8db549_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_425647c9-d913-492c-9e3e-4ff75b8db549" xlink:to="loc_us-gaap_SegmentDomain_425647c9-d913-492c-9e3e-4ff75b8db549_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_6e5cf391-42bb-4ab2-860e-9d5e176bfa67" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_425647c9-d913-492c-9e3e-4ff75b8db549" xlink:to="loc_us-gaap_SegmentDomain_6e5cf391-42bb-4ab2-860e-9d5e176bfa67" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_CrudeOilSegmentMember_7c66f6ff-5471-4541-a92a-217cb2b4fcf1" xlink:href="paa-20211231.xsd#paa_CrudeOilSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_6e5cf391-42bb-4ab2-860e-9d5e176bfa67" xlink:to="loc_paa_CrudeOilSegmentMember_7c66f6ff-5471-4541-a92a-217cb2b4fcf1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_aed3a3d5-82aa-445b-ba87-2824dadf739e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_80bf04fb-9b50-4450-94f0-b0dff1e20746" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_aed3a3d5-82aa-445b-ba87-2824dadf739e" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_aed3a3d5-82aa-445b-ba87-2824dadf739e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_aed3a3d5-82aa-445b-ba87-2824dadf739e" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_aed3a3d5-82aa-445b-ba87-2824dadf739e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_93177784-d823-4cc3-92a9-211e3c7c7e9f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_aed3a3d5-82aa-445b-ba87-2824dadf739e" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_93177784-d823-4cc3-92a9-211e3c7c7e9f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_GainsLossesOnAssetSalesAndAssetImpairmentsNetMember_f75912ce-26f2-48ee-b8a8-cfaf040f7827" xlink:href="paa-20211231.xsd#paa_GainsLossesOnAssetSalesAndAssetImpairmentsNetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_93177784-d823-4cc3-92a9-211e3c7c7e9f" xlink:to="loc_paa_GainsLossesOnAssetSalesAndAssetImpairmentsNetMember_f75912ce-26f2-48ee-b8a8-cfaf040f7827" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_b46a704b-cd33-430e-a1ba-73d33f1e1eaf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_80bf04fb-9b50-4450-94f0-b0dff1e20746" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_b46a704b-cd33-430e-a1ba-73d33f1e1eaf" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_b46a704b-cd33-430e-a1ba-73d33f1e1eaf_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_b46a704b-cd33-430e-a1ba-73d33f1e1eaf" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_b46a704b-cd33-430e-a1ba-73d33f1e1eaf_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_1f3602b0-4d9e-4d78-b79f-bdb35dc7be30" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_b46a704b-cd33-430e-a1ba-73d33f1e1eaf" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_1f3602b0-4d9e-4d78-b79f-bdb35dc7be30" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_ceb293dd-6fbd-456d-86d6-87ed84de5ec7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_1f3602b0-4d9e-4d78-b79f-bdb35dc7be30" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_ceb293dd-6fbd-456d-86d6-87ed84de5ec7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeAxis_62b9a6a9-3e3d-4723-89e0-6478c7d932a8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MeasurementInputTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_80bf04fb-9b50-4450-94f0-b0dff1e20746" xlink:to="loc_us-gaap_MeasurementInputTypeAxis_62b9a6a9-3e3d-4723-89e0-6478c7d932a8" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_62b9a6a9-3e3d-4723-89e0-6478c7d932a8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_62b9a6a9-3e3d-4723-89e0-6478c7d932a8" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_62b9a6a9-3e3d-4723-89e0-6478c7d932a8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_52de23f9-f718-49f8-a4f3-406ebfcc3663" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_62b9a6a9-3e3d-4723-89e0-6478c7d932a8" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_52de23f9-f718-49f8-a4f3-406ebfcc3663" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputDiscountRateMember_6422b07f-ffc2-4020-9bd7-d580e3797da8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MeasurementInputDiscountRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_52de23f9-f718-49f8-a4f3-406ebfcc3663" xlink:to="loc_us-gaap_MeasurementInputDiscountRateMember_6422b07f-ffc2-4020-9bd7-d580e3797da8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationTechniqueAxis_bc29be8a-d4a7-458b-8fa9-4a806e039ce8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ValuationTechniqueAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_80bf04fb-9b50-4450-94f0-b0dff1e20746" xlink:to="loc_us-gaap_ValuationTechniqueAxis_bc29be8a-d4a7-458b-8fa9-4a806e039ce8" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationTechniqueDomain_bc29be8a-d4a7-458b-8fa9-4a806e039ce8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ValuationTechniqueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ValuationTechniqueAxis_bc29be8a-d4a7-458b-8fa9-4a806e039ce8" xlink:to="loc_us-gaap_ValuationTechniqueDomain_bc29be8a-d4a7-458b-8fa9-4a806e039ce8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationTechniqueDomain_714c2478-9788-44a7-bbd8-20238d5d2b0b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ValuationTechniqueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ValuationTechniqueAxis_bc29be8a-d4a7-458b-8fa9-4a806e039ce8" xlink:to="loc_us-gaap_ValuationTechniqueDomain_714c2478-9788-44a7-bbd8-20238d5d2b0b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationTechniqueDiscountedCashFlowMember_af23c281-576f-424e-b043-3732312fc207" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ValuationTechniqueDiscountedCashFlowMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationTechniqueDomain_714c2478-9788-44a7-bbd8-20238d5d2b0b" xlink:to="loc_us-gaap_ValuationTechniqueDiscountedCashFlowMember_af23c281-576f-424e-b043-3732312fc207" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairedLongLivedAssetsHeldAndUsedByTypeAxis_57c426ad-2a97-407e-b2b7-6ef115432470" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ImpairedLongLivedAssetsHeldAndUsedByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_80bf04fb-9b50-4450-94f0-b0dff1e20746" xlink:to="loc_us-gaap_ImpairedLongLivedAssetsHeldAndUsedByTypeAxis_57c426ad-2a97-407e-b2b7-6ef115432470" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairedLongLivedAssetsHeldAndUsedAssetNameDomain_57c426ad-2a97-407e-b2b7-6ef115432470_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ImpairedLongLivedAssetsHeldAndUsedAssetNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ImpairedLongLivedAssetsHeldAndUsedByTypeAxis_57c426ad-2a97-407e-b2b7-6ef115432470" xlink:to="loc_us-gaap_ImpairedLongLivedAssetsHeldAndUsedAssetNameDomain_57c426ad-2a97-407e-b2b7-6ef115432470_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairedLongLivedAssetsHeldAndUsedAssetNameDomain_a9f00ebb-33ae-4c22-a578-742165d43214" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ImpairedLongLivedAssetsHeldAndUsedAssetNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ImpairedLongLivedAssetsHeldAndUsedByTypeAxis_57c426ad-2a97-407e-b2b7-6ef115432470" xlink:to="loc_us-gaap_ImpairedLongLivedAssetsHeldAndUsedAssetNameDomain_a9f00ebb-33ae-4c22-a578-742165d43214" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_CrudeOilStorageTerminalAssetsMember_13ccaad3-2568-4c83-b8d9-a545e002d7d1" xlink:href="paa-20211231.xsd#paa_CrudeOilStorageTerminalAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ImpairedLongLivedAssetsHeldAndUsedAssetNameDomain_a9f00ebb-33ae-4c22-a578-742165d43214" xlink:to="loc_paa_CrudeOilStorageTerminalAssetsMember_13ccaad3-2568-4c83-b8d9-a545e002d7d1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PipelinesMember_9ff8f1cb-1a07-461d-81cf-0c66e8b42abd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PipelinesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ImpairedLongLivedAssetsHeldAndUsedAssetNameDomain_a9f00ebb-33ae-4c22-a578-742165d43214" xlink:to="loc_us-gaap_PipelinesMember_9ff8f1cb-1a07-461d-81cf-0c66e8b42abd" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/AcquisitionsDivestituresandOtherTransactionsJointVentureTransactionDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#AcquisitionsDivestituresandOtherTransactionsJointVentureTransactionDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/AcquisitionsDivestituresandOtherTransactionsJointVentureTransactionDetails" xlink:type="extended" id="ic2eb7b99bcbe46608f6c00bc7dc96e8f_AcquisitionsDivestituresandOtherTransactionsJointVentureTransactionDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_2f3fd30d-cf47-49e1-a6db-e26fc855bc27" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipOwnershipInterest_af24cd80-0949-4749-90d2-389166af9d3a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipOwnershipInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_2f3fd30d-cf47-49e1-a6db-e26fc855bc27" xlink:to="loc_us-gaap_SubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipOwnershipInterest_af24cd80-0949-4749-90d2-389166af9d3a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet_31622343-7f66-4b06-978d-c51b70dc711f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_2f3fd30d-cf47-49e1-a6db-e26fc855bc27" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet_31622343-7f66-4b06-978d-c51b70dc711f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners_6b2352d6-3aaa-413b-b55f-066913c1dba4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_2f3fd30d-cf47-49e1-a6db-e26fc855bc27" xlink:to="loc_us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners_6b2352d6-3aaa-413b-b55f-066913c1dba4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_BusinessCombinationMeasurementInput_7c7e6661-2f43-4296-ab1d-632f3e11ee10" xlink:href="paa-20211231.xsd#paa_BusinessCombinationMeasurementInput"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_2f3fd30d-cf47-49e1-a6db-e26fc855bc27" xlink:to="loc_paa_BusinessCombinationMeasurementInput_7c7e6661-2f43-4296-ab1d-632f3e11ee10" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_e6dcb3b8-5690-4930-8525-8b190288b68b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_2f3fd30d-cf47-49e1-a6db-e26fc855bc27" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_e6dcb3b8-5690-4930-8525-8b190288b68b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_888681da-a526-4c23-aef3-f583bb95db02" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_2f3fd30d-cf47-49e1-a6db-e26fc855bc27" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_888681da-a526-4c23-aef3-f583bb95db02" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentForAmortization_98cee270-32c2-497b-9cc2-c2498dce37b4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AdjustmentForAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_2f3fd30d-cf47-49e1-a6db-e26fc855bc27" xlink:to="loc_us-gaap_AdjustmentForAmortization_98cee270-32c2-497b-9cc2-c2498dce37b4" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationAcquisitionRelatedCosts_f328de6b-eb5b-46f9-9357-d2c3afcf98b0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationAcquisitionRelatedCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_2f3fd30d-cf47-49e1-a6db-e26fc855bc27" xlink:to="loc_us-gaap_BusinessCombinationAcquisitionRelatedCosts_f328de6b-eb5b-46f9-9357-d2c3afcf98b0" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPMembersOrLimitedPartnersOwnershipInterest_b543689a-589e-4183-a2ac-69bdc36bc6ca" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPMembersOrLimitedPartnersOwnershipInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_2f3fd30d-cf47-49e1-a6db-e26fc855bc27" xlink:to="loc_us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPMembersOrLimitedPartnersOwnershipInterest_b543689a-589e-4183-a2ac-69bdc36bc6ca" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferred1_725531f4-5990-4f60-a289-b0030a7c0273" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferred1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_2f3fd30d-cf47-49e1-a6db-e26fc855bc27" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferred1_725531f4-5990-4f60-a289-b0030a7c0273" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_93a3e2fc-8525-4978-9af5-5f6a016fcea6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_2f3fd30d-cf47-49e1-a6db-e26fc855bc27" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_93a3e2fc-8525-4978-9af5-5f6a016fcea6" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_8f5e536d-ebb7-458d-ae81-b4db87095811" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_93a3e2fc-8525-4978-9af5-5f6a016fcea6" xlink:to="loc_srt_CounterpartyNameAxis_8f5e536d-ebb7-458d-ae81-b4db87095811" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_8f5e536d-ebb7-458d-ae81-b4db87095811_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_8f5e536d-ebb7-458d-ae81-b4db87095811" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_8f5e536d-ebb7-458d-ae81-b4db87095811_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_62eedc2e-5cf9-43ab-9024-9a4fa9a3904b" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_8f5e536d-ebb7-458d-ae81-b4db87095811" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_62eedc2e-5cf9-43ab-9024-9a4fa9a3904b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_OryxMidstreamHoldingsLLCMember_5c9932af-8452-4747-ade6-e9b3a4d61026" xlink:href="paa-20211231.xsd#paa_OryxMidstreamHoldingsLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_62eedc2e-5cf9-43ab-9024-9a4fa9a3904b" xlink:to="loc_paa_OryxMidstreamHoldingsLLCMember_5c9932af-8452-4747-ade6-e9b3a4d61026" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_StonepeakInfrastructurePartnersMember_2617723d-5562-4be7-b5de-c7430ea5975b" xlink:href="paa-20211231.xsd#paa_StonepeakInfrastructurePartnersMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_62eedc2e-5cf9-43ab-9024-9a4fa9a3904b" xlink:to="loc_paa_StonepeakInfrastructurePartnersMember_2617723d-5562-4be7-b5de-c7430ea5975b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipAxis_b1fe16cc-1a79-40d6-adae-c08ae166bc06" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_OwnershipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_93a3e2fc-8525-4978-9af5-5f6a016fcea6" xlink:to="loc_srt_OwnershipAxis_b1fe16cc-1a79-40d6-adae-c08ae166bc06" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_b1fe16cc-1a79-40d6-adae-c08ae166bc06_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_OwnershipAxis_b1fe16cc-1a79-40d6-adae-c08ae166bc06" xlink:to="loc_srt_OwnershipDomain_b1fe16cc-1a79-40d6-adae-c08ae166bc06_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_e55eb37f-f4ed-4f09-b091-1e37baf31a43" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_OwnershipAxis_b1fe16cc-1a79-40d6-adae-c08ae166bc06" xlink:to="loc_srt_OwnershipDomain_e55eb37f-f4ed-4f09-b091-1e37baf31a43" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PlainsOryxPermianBasinLLCMember_c98b2a46-7cb4-4a49-a21a-611e1f3131d0" xlink:href="paa-20211231.xsd#paa_PlainsOryxPermianBasinLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_OwnershipDomain_e55eb37f-f4ed-4f09-b091-1e37baf31a43" xlink:to="loc_paa_PlainsOryxPermianBasinLLCMember_c98b2a46-7cb4-4a49-a21a-611e1f3131d0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_OryxMidstreamHoldingsLLCMember_29cfd1b0-0627-466b-98cc-fae7301286a4" xlink:href="paa-20211231.xsd#paa_OryxMidstreamHoldingsLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_OwnershipDomain_e55eb37f-f4ed-4f09-b091-1e37baf31a43" xlink:to="loc_paa_OryxMidstreamHoldingsLLCMember_29cfd1b0-0627-466b-98cc-fae7301286a4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PlainsAllAmericanPipelineLPMember_5fadf1cf-0ba9-40b8-8462-b672f5f8aa5a" xlink:href="paa-20211231.xsd#paa_PlainsAllAmericanPipelineLPMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_OwnershipDomain_e55eb37f-f4ed-4f09-b091-1e37baf31a43" xlink:to="loc_paa_PlainsAllAmericanPipelineLPMember_5fadf1cf-0ba9-40b8-8462-b672f5f8aa5a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransactionTypeAxis_e139530c-fc2a-46eb-b916-f9c4cf601116" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransactionTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_93a3e2fc-8525-4978-9af5-5f6a016fcea6" xlink:to="loc_us-gaap_TransactionTypeAxis_e139530c-fc2a-46eb-b916-f9c4cf601116" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransactionDomain_e139530c-fc2a-46eb-b916-f9c4cf601116_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TransactionTypeAxis_e139530c-fc2a-46eb-b916-f9c4cf601116" xlink:to="loc_us-gaap_TransactionDomain_e139530c-fc2a-46eb-b916-f9c4cf601116_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransactionDomain_a123251e-f63e-4ee8-bb5a-b6b0b249258e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TransactionTypeAxis_e139530c-fc2a-46eb-b916-f9c4cf601116" xlink:to="loc_us-gaap_TransactionDomain_a123251e-f63e-4ee8-bb5a-b6b0b249258e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_JointVentureFormationMember_08cf8b73-8bf9-45ef-a812-1506783e4cae" xlink:href="paa-20211231.xsd#paa_JointVentureFormationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransactionDomain_a123251e-f63e-4ee8-bb5a-b6b0b249258e" xlink:to="loc_paa_JointVentureFormationMember_08cf8b73-8bf9-45ef-a812-1506783e4cae" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_ModifiedSharingArrangementMember_8601d2ed-d6a9-4186-8076-0f1a8f871a26" xlink:href="paa-20211231.xsd#paa_ModifiedSharingArrangementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransactionDomain_a123251e-f63e-4ee8-bb5a-b6b0b249258e" xlink:to="loc_paa_ModifiedSharingArrangementMember_8601d2ed-d6a9-4186-8076-0f1a8f871a26" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_784da458-d3f4-4782-a051-2b40e1f76b3f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_93a3e2fc-8525-4978-9af5-5f6a016fcea6" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_784da458-d3f4-4782-a051-2b40e1f76b3f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_784da458-d3f4-4782-a051-2b40e1f76b3f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_784da458-d3f4-4782-a051-2b40e1f76b3f" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_784da458-d3f4-4782-a051-2b40e1f76b3f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_63621e2d-3e66-4abb-9769-0b0067109bf4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_784da458-d3f4-4782-a051-2b40e1f76b3f" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_63621e2d-3e66-4abb-9769-0b0067109bf4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PlainsOryxPermianBasinLLCMember_ccdf8acb-54d2-4313-9237-ea67eb826917" xlink:href="paa-20211231.xsd#paa_PlainsOryxPermianBasinLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_63621e2d-3e66-4abb-9769-0b0067109bf4" xlink:to="loc_paa_PlainsOryxPermianBasinLLCMember_ccdf8acb-54d2-4313-9237-ea67eb826917" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_83c6872f-854c-4be3-9751-20d6b5f8ee7f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_93a3e2fc-8525-4978-9af5-5f6a016fcea6" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_83c6872f-854c-4be3-9751-20d6b5f8ee7f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_83c6872f-854c-4be3-9751-20d6b5f8ee7f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_83c6872f-854c-4be3-9751-20d6b5f8ee7f" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_83c6872f-854c-4be3-9751-20d6b5f8ee7f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_32615550-b97d-48a3-b263-87c4ad22b0fa" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_83c6872f-854c-4be3-9751-20d6b5f8ee7f" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_32615550-b97d-48a3-b263-87c4ad22b0fa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_50735a64-b053-47bf-8748-2d0abd7b716f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_32615550-b97d-48a3-b263-87c4ad22b0fa" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_50735a64-b053-47bf-8748-2d0abd7b716f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeAxis_2afdc57e-1809-448a-be62-386bcb93df1e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MeasurementInputTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_93a3e2fc-8525-4978-9af5-5f6a016fcea6" xlink:to="loc_us-gaap_MeasurementInputTypeAxis_2afdc57e-1809-448a-be62-386bcb93df1e" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_2afdc57e-1809-448a-be62-386bcb93df1e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_2afdc57e-1809-448a-be62-386bcb93df1e" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_2afdc57e-1809-448a-be62-386bcb93df1e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_8e16e04f-4763-409f-b6dc-142f0aa6541c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_2afdc57e-1809-448a-be62-386bcb93df1e" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_8e16e04f-4763-409f-b6dc-142f0aa6541c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputDiscountRateMember_ea47664b-8da6-4e46-ab34-f7ab551ff0ba" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MeasurementInputDiscountRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_8e16e04f-4763-409f-b6dc-142f0aa6541c" xlink:to="loc_us-gaap_MeasurementInputDiscountRateMember_ea47664b-8da6-4e46-ab34-f7ab551ff0ba" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_MeasurementInputMarketMultipleMember_b1fd38f8-b270-477b-89df-f9559d0770f2" xlink:href="paa-20211231.xsd#paa_MeasurementInputMarketMultipleMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_8e16e04f-4763-409f-b6dc-142f0aa6541c" xlink:to="loc_paa_MeasurementInputMarketMultipleMember_b1fd38f8-b270-477b-89df-f9559d0770f2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationTechniqueAxis_3829a688-4f49-4cfc-b862-417da2d56c0c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ValuationTechniqueAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_93a3e2fc-8525-4978-9af5-5f6a016fcea6" xlink:to="loc_us-gaap_ValuationTechniqueAxis_3829a688-4f49-4cfc-b862-417da2d56c0c" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationTechniqueDomain_3829a688-4f49-4cfc-b862-417da2d56c0c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ValuationTechniqueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ValuationTechniqueAxis_3829a688-4f49-4cfc-b862-417da2d56c0c" xlink:to="loc_us-gaap_ValuationTechniqueDomain_3829a688-4f49-4cfc-b862-417da2d56c0c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationTechniqueDomain_65f7eed1-e037-4488-b9b5-9d20245f7668" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ValuationTechniqueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ValuationTechniqueAxis_3829a688-4f49-4cfc-b862-417da2d56c0c" xlink:to="loc_us-gaap_ValuationTechniqueDomain_65f7eed1-e037-4488-b9b5-9d20245f7668" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationTechniqueDiscountedCashFlowMember_e16af9d3-b110-4378-91bd-c98d37e375f2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ValuationTechniqueDiscountedCashFlowMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationTechniqueDomain_65f7eed1-e037-4488-b9b5-9d20245f7668" xlink:to="loc_us-gaap_ValuationTechniqueDiscountedCashFlowMember_e16af9d3-b110-4378-91bd-c98d37e375f2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MarketApproachValuationTechniqueMember_0ba81cce-5572-40d8-860e-a554ee43c498" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MarketApproachValuationTechniqueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationTechniqueDomain_65f7eed1-e037-4488-b9b5-9d20245f7668" xlink:to="loc_us-gaap_MarketApproachValuationTechniqueMember_0ba81cce-5572-40d8-860e-a554ee43c498" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_25f5934e-ef92-41da-893d-8f388e2eaff6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_93a3e2fc-8525-4978-9af5-5f6a016fcea6" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_25f5934e-ef92-41da-893d-8f388e2eaff6" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_25f5934e-ef92-41da-893d-8f388e2eaff6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_25f5934e-ef92-41da-893d-8f388e2eaff6" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_25f5934e-ef92-41da-893d-8f388e2eaff6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_b848a68c-6019-4b7a-8355-48bfaf34db00" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_25f5934e-ef92-41da-893d-8f388e2eaff6" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_b848a68c-6019-4b7a-8355-48bfaf34db00" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerRelationshipsMember_948adba0-87ea-4ac4-9b17-b7305bbb0b86" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CustomerRelationshipsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_b848a68c-6019-4b7a-8355-48bfaf34db00" xlink:to="loc_us-gaap_CustomerRelationshipsMember_948adba0-87ea-4ac4-9b17-b7305bbb0b86" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_ad3295e3-40ba-4b0b-a148-5110cb3d5901" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_93a3e2fc-8525-4978-9af5-5f6a016fcea6" xlink:to="loc_srt_RangeAxis_ad3295e3-40ba-4b0b-a148-5110cb3d5901" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_ad3295e3-40ba-4b0b-a148-5110cb3d5901_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_ad3295e3-40ba-4b0b-a148-5110cb3d5901" xlink:to="loc_srt_RangeMember_ad3295e3-40ba-4b0b-a148-5110cb3d5901_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_21340686-1140-4eb5-96cc-07d5305da54f" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_ad3295e3-40ba-4b0b-a148-5110cb3d5901" xlink:to="loc_srt_RangeMember_21340686-1140-4eb5-96cc-07d5305da54f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_23b05cbc-b53e-430a-b159-320108b81149" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_21340686-1140-4eb5-96cc-07d5305da54f" xlink:to="loc_srt_MinimumMember_23b05cbc-b53e-430a-b159-320108b81149" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_a177db9a-16d0-423a-92c8-11813b93ffc1" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_21340686-1140-4eb5-96cc-07d5305da54f" xlink:to="loc_srt_MaximumMember_a177db9a-16d0-423a-92c8-11813b93ffc1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_59cb90c7-3fa5-4456-8383-12cd663b08a7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountByClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_93a3e2fc-8525-4978-9af5-5f6a016fcea6" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_59cb90c7-3fa5-4456-8383-12cd663b08a7" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_59cb90c7-3fa5-4456-8383-12cd663b08a7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_59cb90c7-3fa5-4456-8383-12cd663b08a7" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_59cb90c7-3fa5-4456-8383-12cd663b08a7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_586427ef-e412-4be9-8d9a-0a882c690901" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_59cb90c7-3fa5-4456-8383-12cd663b08a7" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_586427ef-e412-4be9-8d9a-0a882c690901" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SeriesAPreferredUnitsMember_183cc397-37d4-4f2f-b372-3826753750f4" xlink:href="paa-20211231.xsd#paa_SeriesAPreferredUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_586427ef-e412-4be9-8d9a-0a882c690901" xlink:to="loc_paa_SeriesAPreferredUnitsMember_183cc397-37d4-4f2f-b372-3826753750f4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnerMember_9d93441b-ad4b-4855-a8fb-acad82307616" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_586427ef-e412-4be9-8d9a-0a882c690901" xlink:to="loc_us-gaap_LimitedPartnerMember_9d93441b-ad4b-4855-a8fb-acad82307616" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_2c4fafd6-db4c-4ac5-a353-0c11a5c4891e" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_93a3e2fc-8525-4978-9af5-5f6a016fcea6" xlink:to="loc_dei_LegalEntityAxis_2c4fafd6-db4c-4ac5-a353-0c11a5c4891e" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_2c4fafd6-db4c-4ac5-a353-0c11a5c4891e_default" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_2c4fafd6-db4c-4ac5-a353-0c11a5c4891e" xlink:to="loc_dei_EntityDomain_2c4fafd6-db4c-4ac5-a353-0c11a5c4891e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_5f8ff99d-eb32-496d-81da-22fe0c516d36" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_2c4fafd6-db4c-4ac5-a353-0c11a5c4891e" xlink:to="loc_dei_EntityDomain_5f8ff99d-eb32-496d-81da-22fe0c516d36" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_OryxMidstreamHoldingsLLCMember_eff19154-4261-4c85-bb91-95d79c92ab90" xlink:href="paa-20211231.xsd#paa_OryxMidstreamHoldingsLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_5f8ff99d-eb32-496d-81da-22fe0c516d36" xlink:to="loc_paa_OryxMidstreamHoldingsLLCMember_eff19154-4261-4c85-bb91-95d79c92ab90" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_StonepeakInfrastructurePartnersAffiliatesMember_2fe5b959-3d57-4a85-b326-d5b94482146a" xlink:href="paa-20211231.xsd#paa_StonepeakInfrastructurePartnersAffiliatesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_5f8ff99d-eb32-496d-81da-22fe0c516d36" xlink:to="loc_paa_StonepeakInfrastructurePartnersAffiliatesMember_2fe5b959-3d57-4a85-b326-d5b94482146a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PlainsOryxPermianBasinLLCMember_8ee9f057-7aaa-40be-8cb5-bc3ac9f34a22" xlink:href="paa-20211231.xsd#paa_PlainsOryxPermianBasinLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_5f8ff99d-eb32-496d-81da-22fe0c516d36" xlink:to="loc_paa_PlainsOryxPermianBasinLLCMember_8ee9f057-7aaa-40be-8cb5-bc3ac9f34a22" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByAssetClassAxis_c96a3ac8-5b50-4e8e-9a41-fe92d9908b32" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByAssetClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_93a3e2fc-8525-4978-9af5-5f6a016fcea6" xlink:to="loc_us-gaap_FairValueByAssetClassAxis_c96a3ac8-5b50-4e8e-9a41-fe92d9908b32" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_c96a3ac8-5b50-4e8e-9a41-fe92d9908b32_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByAssetClassAxis_c96a3ac8-5b50-4e8e-9a41-fe92d9908b32" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_c96a3ac8-5b50-4e8e-9a41-fe92d9908b32_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_69a931c6-d2a3-4a49-97d4-dd324b807dce" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByAssetClassAxis_c96a3ac8-5b50-4e8e-9a41-fe92d9908b32" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_69a931c6-d2a3-4a49-97d4-dd324b807dce" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMember_4df99d13-b36f-4696-a649-220c9474ebfe" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_69a931c6-d2a3-4a49-97d4-dd324b807dce" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMember_4df99d13-b36f-4696-a649-220c9474ebfe" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/AcquisitionsDivestituresandOtherTransactionsPartnersCapitalDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#AcquisitionsDivestituresandOtherTransactionsPartnersCapitalDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/AcquisitionsDivestituresandOtherTransactionsPartnersCapitalDetails" xlink:type="extended" id="iee913afd1bc24688afd323e03a7320fd_AcquisitionsDivestituresandOtherTransactionsPartnersCapitalDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_d50a46cb-2729-4419-b937-25998c60560c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncontrollingInterestIncreaseFromBusinessCombination_e3bf5e74-793c-4c2d-8efe-2b5edbdb1d18" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NoncontrollingInterestIncreaseFromBusinessCombination"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_d50a46cb-2729-4419-b937-25998c60560c" xlink:to="loc_us-gaap_NoncontrollingInterestIncreaseFromBusinessCombination_e3bf5e74-793c-4c2d-8efe-2b5edbdb1d18" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapitalAccountAcquisitions_4dcfa3db-b751-46fe-9480-051e7f7eb440" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnersCapitalAccountAcquisitions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_d50a46cb-2729-4419-b937-25998c60560c" xlink:to="loc_us-gaap_PartnersCapitalAccountAcquisitions_4dcfa3db-b751-46fe-9480-051e7f7eb440" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MembersEquity_d76815c9-6b10-4803-b36b-af9e8be28dd4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MembersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_d50a46cb-2729-4419-b937-25998c60560c" xlink:to="loc_us-gaap_MembersEquity_d76815c9-6b10-4803-b36b-af9e8be28dd4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_a216b710-45bd-45f3-b50c-5a740460f2a5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_d50a46cb-2729-4419-b937-25998c60560c" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_a216b710-45bd-45f3-b50c-5a740460f2a5" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_7ba108f8-ed79-45a5-8291-45dc6b8130ef" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_a216b710-45bd-45f3-b50c-5a740460f2a5" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_7ba108f8-ed79-45a5-8291-45dc6b8130ef" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_7ba108f8-ed79-45a5-8291-45dc6b8130ef_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_7ba108f8-ed79-45a5-8291-45dc6b8130ef" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_7ba108f8-ed79-45a5-8291-45dc6b8130ef_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_75ec90f3-7127-41f5-b81a-1a505377e5fa" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_7ba108f8-ed79-45a5-8291-45dc6b8130ef" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_75ec90f3-7127-41f5-b81a-1a505377e5fa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PlainsOryxPermianBasinLLCMember_eb5d44c5-b39d-455b-b40f-51d22091b6d6" xlink:href="paa-20211231.xsd#paa_PlainsOryxPermianBasinLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_75ec90f3-7127-41f5-b81a-1a505377e5fa" xlink:to="loc_paa_PlainsOryxPermianBasinLLCMember_eb5d44c5-b39d-455b-b40f-51d22091b6d6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_a29f9284-d207-45de-a09e-5525279d1351" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_a216b710-45bd-45f3-b50c-5a740460f2a5" xlink:to="loc_srt_CounterpartyNameAxis_a29f9284-d207-45de-a09e-5525279d1351" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_a29f9284-d207-45de-a09e-5525279d1351_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_a29f9284-d207-45de-a09e-5525279d1351" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_a29f9284-d207-45de-a09e-5525279d1351_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_8b322d95-6c9d-45f9-b97a-e58610a75255" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_a29f9284-d207-45de-a09e-5525279d1351" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_8b322d95-6c9d-45f9-b97a-e58610a75255" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_OryxMidstreamHoldingsLLCMember_76aac459-1fd1-4a06-a10d-c14191a3cb57" xlink:href="paa-20211231.xsd#paa_OryxMidstreamHoldingsLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_8b322d95-6c9d-45f9-b97a-e58610a75255" xlink:to="loc_paa_OryxMidstreamHoldingsLLCMember_76aac459-1fd1-4a06-a10d-c14191a3cb57" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransactionTypeAxis_b29f4440-638b-4713-a53f-285bc24bfd88" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransactionTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_a216b710-45bd-45f3-b50c-5a740460f2a5" xlink:to="loc_us-gaap_TransactionTypeAxis_b29f4440-638b-4713-a53f-285bc24bfd88" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransactionDomain_b29f4440-638b-4713-a53f-285bc24bfd88_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TransactionTypeAxis_b29f4440-638b-4713-a53f-285bc24bfd88" xlink:to="loc_us-gaap_TransactionDomain_b29f4440-638b-4713-a53f-285bc24bfd88_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransactionDomain_646964b0-7f86-40b9-8c51-f21a5f850de8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TransactionTypeAxis_b29f4440-638b-4713-a53f-285bc24bfd88" xlink:to="loc_us-gaap_TransactionDomain_646964b0-7f86-40b9-8c51-f21a5f850de8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_JointVentureFormationMember_765f49c3-01cb-4613-ace1-0698a6624c50" xlink:href="paa-20211231.xsd#paa_JointVentureFormationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransactionDomain_646964b0-7f86-40b9-8c51-f21a5f850de8" xlink:to="loc_paa_JointVentureFormationMember_765f49c3-01cb-4613-ace1-0698a6624c50" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerCapitalComponentsAxis_a2f2dbc6-3d53-4435-87be-eab6e7513c4c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnerCapitalComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_a216b710-45bd-45f3-b50c-5a740460f2a5" xlink:to="loc_us-gaap_PartnerCapitalComponentsAxis_a2f2dbc6-3d53-4435-87be-eab6e7513c4c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerCapitalComponentsDomain_a2f2dbc6-3d53-4435-87be-eab6e7513c4c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnerCapitalComponentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PartnerCapitalComponentsAxis_a2f2dbc6-3d53-4435-87be-eab6e7513c4c" xlink:to="loc_us-gaap_PartnerCapitalComponentsDomain_a2f2dbc6-3d53-4435-87be-eab6e7513c4c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerCapitalComponentsDomain_37e47996-bb3a-4a27-8dc1-7fc7723c54cb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnerCapitalComponentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PartnerCapitalComponentsAxis_a2f2dbc6-3d53-4435-87be-eab6e7513c4c" xlink:to="loc_us-gaap_PartnerCapitalComponentsDomain_37e47996-bb3a-4a27-8dc1-7fc7723c54cb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncontrollingInterestMember_2d506f98-2da1-40ff-8335-62a04f911247" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NoncontrollingInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnerCapitalComponentsDomain_37e47996-bb3a-4a27-8dc1-7fc7723c54cb" xlink:to="loc_us-gaap_NoncontrollingInterestMember_2d506f98-2da1-40ff-8335-62a04f911247" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ParentMember_30b670e6-194e-457e-889c-500d621c5857" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ParentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnerCapitalComponentsDomain_37e47996-bb3a-4a27-8dc1-7fc7723c54cb" xlink:to="loc_us-gaap_ParentMember_30b670e6-194e-457e-889c-500d621c5857" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_b264deff-a90f-41de-9f33-91d4fe75a0a4" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_a216b710-45bd-45f3-b50c-5a740460f2a5" xlink:to="loc_dei_LegalEntityAxis_b264deff-a90f-41de-9f33-91d4fe75a0a4" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_b264deff-a90f-41de-9f33-91d4fe75a0a4_default" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_b264deff-a90f-41de-9f33-91d4fe75a0a4" xlink:to="loc_dei_EntityDomain_b264deff-a90f-41de-9f33-91d4fe75a0a4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_f87e6a8a-2138-4eee-a671-aea9fa0fe152" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_b264deff-a90f-41de-9f33-91d4fe75a0a4" xlink:to="loc_dei_EntityDomain_f87e6a8a-2138-4eee-a671-aea9fa0fe152" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_OryxMidstreamHoldingsLLCMember_ab934f86-3f83-47aa-84c5-65867f8b025c" xlink:href="paa-20211231.xsd#paa_OryxMidstreamHoldingsLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_f87e6a8a-2138-4eee-a671-aea9fa0fe152" xlink:to="loc_paa_OryxMidstreamHoldingsLLCMember_ab934f86-3f83-47aa-84c5-65867f8b025c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PlainsOryxPermianBasinLLCMember_ee8279e3-b9ec-463f-b278-4bc3864c6432" xlink:href="paa-20211231.xsd#paa_PlainsOryxPermianBasinLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_f87e6a8a-2138-4eee-a671-aea9fa0fe152" xlink:to="loc_paa_PlainsOryxPermianBasinLLCMember_ee8279e3-b9ec-463f-b278-4bc3864c6432" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/AcquisitionsDivestituresandOtherTransactionsAssetsAcquiredandLiabilitiesAssumedDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#AcquisitionsDivestituresandOtherTransactionsAssetsAcquiredandLiabilitiesAssumedDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/AcquisitionsDivestituresandOtherTransactionsAssetsAcquiredandLiabilitiesAssumedDetails" xlink:type="extended" id="i4c976d0bee964f5981fd03782cf1bb9d_AcquisitionsDivestituresandOtherTransactionsAssetsAcquiredandLiabilitiesAssumedDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_5b7df7a2-a0ed-44bd-93d4-0cfd97672d3d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment_2e1e3aec-a767-4fce-bfec-db39175b31c9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_5b7df7a2-a0ed-44bd-93d4-0cfd97672d3d" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment_2e1e3aec-a767-4fce-bfec-db39175b31c9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles_8442194e-83ca-4352-99d9-2c2a6c8fc15e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_5b7df7a2-a0ed-44bd-93d4-0cfd97672d3d" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles_8442194e-83ca-4352-99d9-2c2a6c8fc15e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInvestmentInUnconsolidatedEntities_c0ea03e8-ca67-4dcc-8b1f-97fdfdd7c7c8" xlink:href="paa-20211231.xsd#paa_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInvestmentInUnconsolidatedEntities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_5b7df7a2-a0ed-44bd-93d4-0cfd97672d3d" xlink:to="loc_paa_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInvestmentInUnconsolidatedEntities_c0ea03e8-ca67-4dcc-8b1f-97fdfdd7c7c8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLinefill_f9b786bc-d405-4d53-b688-1fc583b01e53" xlink:href="paa-20211231.xsd#paa_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLinefill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_5b7df7a2-a0ed-44bd-93d4-0cfd97672d3d" xlink:to="loc_paa_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLinefill_f9b786bc-d405-4d53-b688-1fc583b01e53" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedWorkingCapitalAndOtherAssetsAndLiabilities_4de88927-87d4-47e0-8283-7756fdd9c742" xlink:href="paa-20211231.xsd#paa_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedWorkingCapitalAndOtherAssetsAndLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_5b7df7a2-a0ed-44bd-93d4-0cfd97672d3d" xlink:to="loc_paa_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedWorkingCapitalAndOtherAssetsAndLiabilities_4de88927-87d4-47e0-8283-7756fdd9c742" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet_8248ad9e-d063-4db4-9090-4718a97baedb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_5b7df7a2-a0ed-44bd-93d4-0cfd97672d3d" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet_8248ad9e-d063-4db4-9090-4718a97baedb" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_69b46e9d-a0b7-43bf-82ef-a933710f3938" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_5b7df7a2-a0ed-44bd-93d4-0cfd97672d3d" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_69b46e9d-a0b7-43bf-82ef-a933710f3938" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_7d8aff54-a468-4e20-8ca3-f4f143ff8ac5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_5b7df7a2-a0ed-44bd-93d4-0cfd97672d3d" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_7d8aff54-a468-4e20-8ca3-f4f143ff8ac5" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_70960573-a311-4c4a-8295-e8e6a56704f3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_5b7df7a2-a0ed-44bd-93d4-0cfd97672d3d" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_70960573-a311-4c4a-8295-e8e6a56704f3" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_142ee658-4319-4abb-a5b8-07203ae54d3d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_70960573-a311-4c4a-8295-e8e6a56704f3" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_142ee658-4319-4abb-a5b8-07203ae54d3d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_142ee658-4319-4abb-a5b8-07203ae54d3d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_142ee658-4319-4abb-a5b8-07203ae54d3d" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_142ee658-4319-4abb-a5b8-07203ae54d3d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_01defc43-75aa-4323-9b21-79752aedb73a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_142ee658-4319-4abb-a5b8-07203ae54d3d" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_01defc43-75aa-4323-9b21-79752aedb73a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PlainsOryxPermianBasinLLCMember_d6ed715d-ea8c-425f-a824-9aa59ef1be4b" xlink:href="paa-20211231.xsd#paa_PlainsOryxPermianBasinLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_01defc43-75aa-4323-9b21-79752aedb73a" xlink:to="loc_paa_PlainsOryxPermianBasinLLCMember_d6ed715d-ea8c-425f-a824-9aa59ef1be4b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_2e7de668-fd36-4077-9fcd-d603851afa31" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_70960573-a311-4c4a-8295-e8e6a56704f3" xlink:to="loc_srt_CounterpartyNameAxis_2e7de668-fd36-4077-9fcd-d603851afa31" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_2e7de668-fd36-4077-9fcd-d603851afa31_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_2e7de668-fd36-4077-9fcd-d603851afa31" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_2e7de668-fd36-4077-9fcd-d603851afa31_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_2201d5f7-ad27-4e1e-9a7b-bca755acecbd" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_2e7de668-fd36-4077-9fcd-d603851afa31" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_2201d5f7-ad27-4e1e-9a7b-bca755acecbd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_OryxMidstreamHoldingsLLCMember_b6dc9a00-4566-45e2-b3ea-9afa3686cdae" xlink:href="paa-20211231.xsd#paa_OryxMidstreamHoldingsLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_2201d5f7-ad27-4e1e-9a7b-bca755acecbd" xlink:to="loc_paa_OryxMidstreamHoldingsLLCMember_b6dc9a00-4566-45e2-b3ea-9afa3686cdae" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransactionTypeAxis_ab32db0d-5255-4f7c-8925-38941cd5a153" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransactionTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_70960573-a311-4c4a-8295-e8e6a56704f3" xlink:to="loc_us-gaap_TransactionTypeAxis_ab32db0d-5255-4f7c-8925-38941cd5a153" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransactionDomain_ab32db0d-5255-4f7c-8925-38941cd5a153_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TransactionTypeAxis_ab32db0d-5255-4f7c-8925-38941cd5a153" xlink:to="loc_us-gaap_TransactionDomain_ab32db0d-5255-4f7c-8925-38941cd5a153_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransactionDomain_c3940054-092e-42da-a2ba-4887d8203640" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TransactionTypeAxis_ab32db0d-5255-4f7c-8925-38941cd5a153" xlink:to="loc_us-gaap_TransactionDomain_c3940054-092e-42da-a2ba-4887d8203640" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_JointVentureFormationMember_42645c46-4ec3-4440-8c10-f565e48bd5fa" xlink:href="paa-20211231.xsd#paa_JointVentureFormationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransactionDomain_c3940054-092e-42da-a2ba-4887d8203640" xlink:to="loc_paa_JointVentureFormationMember_42645c46-4ec3-4440-8c10-f565e48bd5fa" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_c68f88dd-18c9-4074-89a5-c14cc5b92a7b" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_70960573-a311-4c4a-8295-e8e6a56704f3" xlink:to="loc_srt_RangeAxis_c68f88dd-18c9-4074-89a5-c14cc5b92a7b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_c68f88dd-18c9-4074-89a5-c14cc5b92a7b_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_c68f88dd-18c9-4074-89a5-c14cc5b92a7b" xlink:to="loc_srt_RangeMember_c68f88dd-18c9-4074-89a5-c14cc5b92a7b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_6bfaec3c-3487-4848-94ae-f025d9ed56d0" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_c68f88dd-18c9-4074-89a5-c14cc5b92a7b" xlink:to="loc_srt_RangeMember_6bfaec3c-3487-4848-94ae-f025d9ed56d0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_891d0b4e-22e2-469c-986c-9ef05cca5660" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_6bfaec3c-3487-4848-94ae-f025d9ed56d0" xlink:to="loc_srt_MinimumMember_891d0b4e-22e2-469c-986c-9ef05cca5660" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_05aba6e2-c2a3-4580-b11e-a5b3d1e8faea" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_6bfaec3c-3487-4848-94ae-f025d9ed56d0" xlink:to="loc_srt_MaximumMember_05aba6e2-c2a3-4580-b11e-a5b3d1e8faea" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_250801b5-ffc5-4d73-a4b0-35e554eb0ac1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_70960573-a311-4c4a-8295-e8e6a56704f3" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_250801b5-ffc5-4d73-a4b0-35e554eb0ac1" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_250801b5-ffc5-4d73-a4b0-35e554eb0ac1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_250801b5-ffc5-4d73-a4b0-35e554eb0ac1" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_250801b5-ffc5-4d73-a4b0-35e554eb0ac1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_21c806d6-6067-4ea3-9b57-7ab289ddfd13" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_250801b5-ffc5-4d73-a4b0-35e554eb0ac1" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_21c806d6-6067-4ea3-9b57-7ab289ddfd13" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_e9ac5d9b-0aaa-4964-9c2b-88e9157026dc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_21c806d6-6067-4ea3-9b57-7ab289ddfd13" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_e9ac5d9b-0aaa-4964-9c2b-88e9157026dc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeAxis_fec695a9-2e69-483c-8b6d-5f55e518d0a0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MeasurementInputTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_70960573-a311-4c4a-8295-e8e6a56704f3" xlink:to="loc_us-gaap_MeasurementInputTypeAxis_fec695a9-2e69-483c-8b6d-5f55e518d0a0" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_fec695a9-2e69-483c-8b6d-5f55e518d0a0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_fec695a9-2e69-483c-8b6d-5f55e518d0a0" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_fec695a9-2e69-483c-8b6d-5f55e518d0a0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_c4d94c08-f3c6-4da5-ad21-ece1cbaa6043" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_fec695a9-2e69-483c-8b6d-5f55e518d0a0" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_c4d94c08-f3c6-4da5-ad21-ece1cbaa6043" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputDiscountRateMember_e8824e68-cab7-4a18-be2f-4bf34ed13b4d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MeasurementInputDiscountRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_c4d94c08-f3c6-4da5-ad21-ece1cbaa6043" xlink:to="loc_us-gaap_MeasurementInputDiscountRateMember_e8824e68-cab7-4a18-be2f-4bf34ed13b4d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationTechniqueAxis_059a30c7-ee09-42c6-9779-3ae88011abb3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ValuationTechniqueAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_70960573-a311-4c4a-8295-e8e6a56704f3" xlink:to="loc_us-gaap_ValuationTechniqueAxis_059a30c7-ee09-42c6-9779-3ae88011abb3" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationTechniqueDomain_059a30c7-ee09-42c6-9779-3ae88011abb3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ValuationTechniqueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ValuationTechniqueAxis_059a30c7-ee09-42c6-9779-3ae88011abb3" xlink:to="loc_us-gaap_ValuationTechniqueDomain_059a30c7-ee09-42c6-9779-3ae88011abb3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationTechniqueDomain_442f9c02-bcf8-49cf-8ede-540f00efd835" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ValuationTechniqueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ValuationTechniqueAxis_059a30c7-ee09-42c6-9779-3ae88011abb3" xlink:to="loc_us-gaap_ValuationTechniqueDomain_442f9c02-bcf8-49cf-8ede-540f00efd835" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationTechniqueDiscountedCashFlowMember_05c7dce2-ac20-424d-892d-d72c46bcb890" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ValuationTechniqueDiscountedCashFlowMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationTechniqueDomain_442f9c02-bcf8-49cf-8ede-540f00efd835" xlink:to="loc_us-gaap_ValuationTechniqueDiscountedCashFlowMember_05c7dce2-ac20-424d-892d-d72c46bcb890" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/AcquisitionsDivestituresandOtherTransactionsFutureAmortizationExpenseDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#AcquisitionsDivestituresandOtherTransactionsFutureAmortizationExpenseDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/AcquisitionsDivestituresandOtherTransactionsFutureAmortizationExpenseDetails" xlink:type="extended" id="ic4fd85799a4a43a69b63765931157497_AcquisitionsDivestituresandOtherTransactionsFutureAmortizationExpenseDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_a5caabda-bd2e-4abc-b6b8-f63e1fd11e73" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths_7e8a7566-93d9-49f0-aa8b-8fbf1b2ca667" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_a5caabda-bd2e-4abc-b6b8-f63e1fd11e73" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths_7e8a7566-93d9-49f0-aa8b-8fbf1b2ca667" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_c6d07711-0b55-4942-ae8a-eb092676a6a5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_a5caabda-bd2e-4abc-b6b8-f63e1fd11e73" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_c6d07711-0b55-4942-ae8a-eb092676a6a5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_7d10f28e-54ea-4347-bb82-9799397101f9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_a5caabda-bd2e-4abc-b6b8-f63e1fd11e73" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_7d10f28e-54ea-4347-bb82-9799397101f9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour_9c1032e6-641f-4dd2-9004-172373a6b173" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_a5caabda-bd2e-4abc-b6b8-f63e1fd11e73" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour_9c1032e6-641f-4dd2-9004-172373a6b173" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive_ff026ecf-67d9-4448-a0e4-cfa09bfdd139" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_a5caabda-bd2e-4abc-b6b8-f63e1fd11e73" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive_ff026ecf-67d9-4448-a0e4-cfa09bfdd139" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_e8b75a50-516c-40e6-af95-9ae755617c28" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_a5caabda-bd2e-4abc-b6b8-f63e1fd11e73" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_e8b75a50-516c-40e6-af95-9ae755617c28" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_1ede498a-3594-49bb-a3a4-de22daa35d3c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_e8b75a50-516c-40e6-af95-9ae755617c28" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_1ede498a-3594-49bb-a3a4-de22daa35d3c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_1ede498a-3594-49bb-a3a4-de22daa35d3c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_1ede498a-3594-49bb-a3a4-de22daa35d3c" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_1ede498a-3594-49bb-a3a4-de22daa35d3c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_fb7d86c8-46e2-45fb-942c-283adcda9ae1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_1ede498a-3594-49bb-a3a4-de22daa35d3c" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_fb7d86c8-46e2-45fb-942c-283adcda9ae1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerRelationshipsMember_4e5e3b70-b496-4fe5-8e34-65b2edff7b29" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CustomerRelationshipsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_fb7d86c8-46e2-45fb-942c-283adcda9ae1" xlink:to="loc_us-gaap_CustomerRelationshipsMember_4e5e3b70-b496-4fe5-8e34-65b2edff7b29" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_758a10c0-c08f-4c6a-8fd0-c725de77088f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_e8b75a50-516c-40e6-af95-9ae755617c28" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_758a10c0-c08f-4c6a-8fd0-c725de77088f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_758a10c0-c08f-4c6a-8fd0-c725de77088f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_758a10c0-c08f-4c6a-8fd0-c725de77088f" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_758a10c0-c08f-4c6a-8fd0-c725de77088f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_9e50a1bd-5779-42e8-97a3-08cce7da7467" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_758a10c0-c08f-4c6a-8fd0-c725de77088f" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_9e50a1bd-5779-42e8-97a3-08cce7da7467" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PlainsOryxPermianBasinLLCMember_a623d106-e680-45c4-a8a4-c4a493af2815" xlink:href="paa-20211231.xsd#paa_PlainsOryxPermianBasinLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_9e50a1bd-5779-42e8-97a3-08cce7da7467" xlink:to="loc_paa_PlainsOryxPermianBasinLLCMember_a623d106-e680-45c4-a8a4-c4a493af2815" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_a83dad61-0e1f-436e-9925-630b06842c52" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_e8b75a50-516c-40e6-af95-9ae755617c28" xlink:to="loc_srt_CounterpartyNameAxis_a83dad61-0e1f-436e-9925-630b06842c52" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_a83dad61-0e1f-436e-9925-630b06842c52_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_a83dad61-0e1f-436e-9925-630b06842c52" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_a83dad61-0e1f-436e-9925-630b06842c52_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_f915fcad-98ab-477b-902f-cbac61901646" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_a83dad61-0e1f-436e-9925-630b06842c52" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_f915fcad-98ab-477b-902f-cbac61901646" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_OryxMidstreamHoldingsLLCMember_d5a37632-c0ec-48ac-94df-510073f2684f" xlink:href="paa-20211231.xsd#paa_OryxMidstreamHoldingsLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_f915fcad-98ab-477b-902f-cbac61901646" xlink:to="loc_paa_OryxMidstreamHoldingsLLCMember_d5a37632-c0ec-48ac-94df-510073f2684f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransactionTypeAxis_27e0f22b-79f7-4372-a76d-f5c266674a18" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransactionTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_e8b75a50-516c-40e6-af95-9ae755617c28" xlink:to="loc_us-gaap_TransactionTypeAxis_27e0f22b-79f7-4372-a76d-f5c266674a18" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransactionDomain_27e0f22b-79f7-4372-a76d-f5c266674a18_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TransactionTypeAxis_27e0f22b-79f7-4372-a76d-f5c266674a18" xlink:to="loc_us-gaap_TransactionDomain_27e0f22b-79f7-4372-a76d-f5c266674a18_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransactionDomain_77cb6ff2-39f6-4e80-a5c4-0b99382aef05" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TransactionTypeAxis_27e0f22b-79f7-4372-a76d-f5c266674a18" xlink:to="loc_us-gaap_TransactionDomain_77cb6ff2-39f6-4e80-a5c4-0b99382aef05" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_JointVentureFormationMember_56ee7b41-c230-4649-8630-b5a7d9b731c7" xlink:href="paa-20211231.xsd#paa_JointVentureFormationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransactionDomain_77cb6ff2-39f6-4e80-a5c4-0b99382aef05" xlink:to="loc_paa_JointVentureFormationMember_56ee7b41-c230-4649-8630-b5a7d9b731c7" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/AcquisitionsDivestituresandOtherTransactionsModifiedSharingArrangementDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#AcquisitionsDivestituresandOtherTransactionsModifiedSharingArrangementDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/AcquisitionsDivestituresandOtherTransactionsModifiedSharingArrangementDetails" xlink:type="extended" id="icaaac549ea6141ea935a7200bf293996_AcquisitionsDivestituresandOtherTransactionsModifiedSharingArrangementDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_85815eb9-5518-451a-999c-6c1c5579ed07" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_ModifiedSharingArrangementTerm_3b00c9f6-962e-4fb7-81a7-04f5c52a2827" xlink:href="paa-20211231.xsd#paa_ModifiedSharingArrangementTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_85815eb9-5518-451a-999c-6c1c5579ed07" xlink:to="loc_paa_ModifiedSharingArrangementTerm_3b00c9f6-962e-4fb7-81a7-04f5c52a2827" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_DistributionPercentageAfterTerminationOfModifiedSharingArrangement_01ce468d-ab12-4251-91f1-159afbe023a7" xlink:href="paa-20211231.xsd#paa_DistributionPercentageAfterTerminationOfModifiedSharingArrangement"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_85815eb9-5518-451a-999c-6c1c5579ed07" xlink:to="loc_paa_DistributionPercentageAfterTerminationOfModifiedSharingArrangement_01ce468d-ab12-4251-91f1-159afbe023a7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_ModifiedSharingArrangementDistributionPercentage_ed42fa7f-6f38-4bff-b52d-f7940db86fea" xlink:href="paa-20211231.xsd#paa_ModifiedSharingArrangementDistributionPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_85815eb9-5518-451a-999c-6c1c5579ed07" xlink:to="loc_paa_ModifiedSharingArrangementDistributionPercentage_ed42fa7f-6f38-4bff-b52d-f7940db86fea" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_d81c6e7c-fb78-4e20-830e-fa98fa325f18" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_85815eb9-5518-451a-999c-6c1c5579ed07" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_d81c6e7c-fb78-4e20-830e-fa98fa325f18" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_22e6e2d7-c38a-4258-9ea8-e791e77977f5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_d81c6e7c-fb78-4e20-830e-fa98fa325f18" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_22e6e2d7-c38a-4258-9ea8-e791e77977f5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_22e6e2d7-c38a-4258-9ea8-e791e77977f5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_22e6e2d7-c38a-4258-9ea8-e791e77977f5" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_22e6e2d7-c38a-4258-9ea8-e791e77977f5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_30e038a4-c12f-4196-979f-04d1b8a4de08" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_22e6e2d7-c38a-4258-9ea8-e791e77977f5" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_30e038a4-c12f-4196-979f-04d1b8a4de08" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PlainsOryxPermianBasinLLCMember_9a73a69f-9f4f-482b-850d-91102319a05a" xlink:href="paa-20211231.xsd#paa_PlainsOryxPermianBasinLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_30e038a4-c12f-4196-979f-04d1b8a4de08" xlink:to="loc_paa_PlainsOryxPermianBasinLLCMember_9a73a69f-9f4f-482b-850d-91102319a05a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_f348c407-9c46-46b0-876d-c3184b7a4f9c" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_d81c6e7c-fb78-4e20-830e-fa98fa325f18" xlink:to="loc_dei_LegalEntityAxis_f348c407-9c46-46b0-876d-c3184b7a4f9c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_f348c407-9c46-46b0-876d-c3184b7a4f9c_default" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_f348c407-9c46-46b0-876d-c3184b7a4f9c" xlink:to="loc_dei_EntityDomain_f348c407-9c46-46b0-876d-c3184b7a4f9c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_b3cb2ba4-91ae-4d8e-b135-c6af66c9955a" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_f348c407-9c46-46b0-876d-c3184b7a4f9c" xlink:to="loc_dei_EntityDomain_b3cb2ba4-91ae-4d8e-b135-c6af66c9955a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_OryxMidstreamHoldingsLLCMember_0b82e729-c302-46ba-977a-a07429086a0f" xlink:href="paa-20211231.xsd#paa_OryxMidstreamHoldingsLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_b3cb2ba4-91ae-4d8e-b135-c6af66c9955a" xlink:to="loc_paa_OryxMidstreamHoldingsLLCMember_0b82e729-c302-46ba-977a-a07429086a0f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransactionTypeAxis_96cfe0d9-9515-494c-b36f-991767abfd38" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransactionTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_d81c6e7c-fb78-4e20-830e-fa98fa325f18" xlink:to="loc_us-gaap_TransactionTypeAxis_96cfe0d9-9515-494c-b36f-991767abfd38" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransactionDomain_96cfe0d9-9515-494c-b36f-991767abfd38_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TransactionTypeAxis_96cfe0d9-9515-494c-b36f-991767abfd38" xlink:to="loc_us-gaap_TransactionDomain_96cfe0d9-9515-494c-b36f-991767abfd38_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransactionDomain_5b0dcba0-086e-4e0c-b781-63f22a4d6332" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TransactionTypeAxis_96cfe0d9-9515-494c-b36f-991767abfd38" xlink:to="loc_us-gaap_TransactionDomain_5b0dcba0-086e-4e0c-b781-63f22a4d6332" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_JointVentureFormationMember_ff19b8b0-8cf2-4404-bd58-5c6b849306ef" xlink:href="paa-20211231.xsd#paa_JointVentureFormationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransactionDomain_5b0dcba0-086e-4e0c-b781-63f22a4d6332" xlink:to="loc_paa_JointVentureFormationMember_ff19b8b0-8cf2-4404-bd58-5c6b849306ef" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_ModifiedSharingArrangementMember_e8f13cbf-89ce-4554-9d01-0c637aeb1ab7" xlink:href="paa-20211231.xsd#paa_ModifiedSharingArrangementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransactionDomain_5b0dcba0-086e-4e0c-b781-63f22a4d6332" xlink:to="loc_paa_ModifiedSharingArrangementMember_e8f13cbf-89ce-4554-9d01-0c637aeb1ab7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_ModifiedSharingArrangementAnnualAvailableCashAxis_b30a73fe-1b6a-499a-ad38-e77974d48f13" xlink:href="paa-20211231.xsd#paa_ModifiedSharingArrangementAnnualAvailableCashAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_d81c6e7c-fb78-4e20-830e-fa98fa325f18" xlink:to="loc_paa_ModifiedSharingArrangementAnnualAvailableCashAxis_b30a73fe-1b6a-499a-ad38-e77974d48f13" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_ModifiedSharingArrangementAnnualAvailableCashDomain_b30a73fe-1b6a-499a-ad38-e77974d48f13_default" xlink:href="paa-20211231.xsd#paa_ModifiedSharingArrangementAnnualAvailableCashDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_paa_ModifiedSharingArrangementAnnualAvailableCashAxis_b30a73fe-1b6a-499a-ad38-e77974d48f13" xlink:to="loc_paa_ModifiedSharingArrangementAnnualAvailableCashDomain_b30a73fe-1b6a-499a-ad38-e77974d48f13_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_ModifiedSharingArrangementAnnualAvailableCashDomain_3146831f-7c5c-4e40-a139-6a403d197bb2" xlink:href="paa-20211231.xsd#paa_ModifiedSharingArrangementAnnualAvailableCashDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_paa_ModifiedSharingArrangementAnnualAvailableCashAxis_b30a73fe-1b6a-499a-ad38-e77974d48f13" xlink:to="loc_paa_ModifiedSharingArrangementAnnualAvailableCashDomain_3146831f-7c5c-4e40-a139-6a403d197bb2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_ModifiedSharingArrangementAnnualAvailableCashUpTo300MillionMember_972df248-4d42-4e62-a022-9fd7d0c72007" xlink:href="paa-20211231.xsd#paa_ModifiedSharingArrangementAnnualAvailableCashUpTo300MillionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_ModifiedSharingArrangementAnnualAvailableCashDomain_3146831f-7c5c-4e40-a139-6a403d197bb2" xlink:to="loc_paa_ModifiedSharingArrangementAnnualAvailableCashUpTo300MillionMember_972df248-4d42-4e62-a022-9fd7d0c72007" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_ModifiedSharingArrangementAnnualAvailableCashBetween300MillionTo428MillionMember_f0f1054b-1afe-4794-96d2-15e659b3c44d" xlink:href="paa-20211231.xsd#paa_ModifiedSharingArrangementAnnualAvailableCashBetween300MillionTo428MillionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_ModifiedSharingArrangementAnnualAvailableCashDomain_3146831f-7c5c-4e40-a139-6a403d197bb2" xlink:to="loc_paa_ModifiedSharingArrangementAnnualAvailableCashBetween300MillionTo428MillionMember_f0f1054b-1afe-4794-96d2-15e659b3c44d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_ModifiedRevenueArrangementAnnualAvailableCashBetween428MillionTo815MillionMember_4abc3125-5a4a-4323-9c19-b5fe149eceb9" xlink:href="paa-20211231.xsd#paa_ModifiedRevenueArrangementAnnualAvailableCashBetween428MillionTo815MillionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_ModifiedSharingArrangementAnnualAvailableCashDomain_3146831f-7c5c-4e40-a139-6a403d197bb2" xlink:to="loc_paa_ModifiedRevenueArrangementAnnualAvailableCashBetween428MillionTo815MillionMember_4abc3125-5a4a-4323-9c19-b5fe149eceb9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_ModifiedSharingArrangementAnnualAvailableCash815MillionAndAboveMember_86524f86-e828-48e7-ab82-2adab36ba824" xlink:href="paa-20211231.xsd#paa_ModifiedSharingArrangementAnnualAvailableCash815MillionAndAboveMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_ModifiedSharingArrangementAnnualAvailableCashDomain_3146831f-7c5c-4e40-a139-6a403d197bb2" xlink:to="loc_paa_ModifiedSharingArrangementAnnualAvailableCash815MillionAndAboveMember_86524f86-e828-48e7-ab82-2adab36ba824" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_561848fd-6417-445b-a678-5ec3ca9ad530" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_d81c6e7c-fb78-4e20-830e-fa98fa325f18" xlink:to="loc_srt_CounterpartyNameAxis_561848fd-6417-445b-a678-5ec3ca9ad530" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_561848fd-6417-445b-a678-5ec3ca9ad530_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_561848fd-6417-445b-a678-5ec3ca9ad530" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_561848fd-6417-445b-a678-5ec3ca9ad530_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_ea82646d-45d2-491e-b7c1-f4df0abeadf7" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_561848fd-6417-445b-a678-5ec3ca9ad530" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_ea82646d-45d2-491e-b7c1-f4df0abeadf7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_OryxMidstreamHoldingsLLCMember_b14be9e4-d4e3-4e63-a973-16f16ceaa611" xlink:href="paa-20211231.xsd#paa_OryxMidstreamHoldingsLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_ea82646d-45d2-491e-b7c1-f4df0abeadf7" xlink:to="loc_paa_OryxMidstreamHoldingsLLCMember_b14be9e4-d4e3-4e63-a973-16f16ceaa611" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_835594ef-441b-44ed-b1cd-89ae7b2d5a60" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_d81c6e7c-fb78-4e20-830e-fa98fa325f18" xlink:to="loc_srt_RangeAxis_835594ef-441b-44ed-b1cd-89ae7b2d5a60" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_835594ef-441b-44ed-b1cd-89ae7b2d5a60_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_835594ef-441b-44ed-b1cd-89ae7b2d5a60" xlink:to="loc_srt_RangeMember_835594ef-441b-44ed-b1cd-89ae7b2d5a60_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_9fe85ed9-969f-492f-9693-ad645591b6d7" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_835594ef-441b-44ed-b1cd-89ae7b2d5a60" xlink:to="loc_srt_RangeMember_9fe85ed9-969f-492f-9693-ad645591b6d7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_e0deba37-4bf1-4709-9efb-4fea23265993" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_9fe85ed9-969f-492f-9693-ad645591b6d7" xlink:to="loc_srt_MaximumMember_e0deba37-4bf1-4709-9efb-4fea23265993" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/AcquisitionsDivestituresandOtherTransactionsProFormaDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#AcquisitionsDivestituresandOtherTransactionsProFormaDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/AcquisitionsDivestituresandOtherTransactionsProFormaDetails" xlink:type="extended" id="id1e50910d15846cf904f2f2b737c591c_AcquisitionsDivestituresandOtherTransactionsProFormaDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_f7004a7c-de91-4161-b5d1-1602b92ae53d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionsProFormaRevenue_5166c906-1ff5-4c88-87bc-408155aa96f8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionsProFormaRevenue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_f7004a7c-de91-4161-b5d1-1602b92ae53d" xlink:to="loc_us-gaap_BusinessAcquisitionsProFormaRevenue_5166c906-1ff5-4c88-87bc-408155aa96f8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_BusinessCombinationProFormaNetIncomeLossAttributableToTheParent_83d2fd15-a35c-4309-9a16-3944c0723f2b" xlink:href="paa-20211231.xsd#paa_BusinessCombinationProFormaNetIncomeLossAttributableToTheParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_f7004a7c-de91-4161-b5d1-1602b92ae53d" xlink:to="loc_paa_BusinessCombinationProFormaNetIncomeLossAttributableToTheParent_83d2fd15-a35c-4309-9a16-3944c0723f2b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_BusinessAcquisitionProFormaNetIncomeLossAllocatedToCommonUnitholdersBasic_90c6f5e4-51fd-4056-bbc5-7aa8f1a46a82" xlink:href="paa-20211231.xsd#paa_BusinessAcquisitionProFormaNetIncomeLossAllocatedToCommonUnitholdersBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_f7004a7c-de91-4161-b5d1-1602b92ae53d" xlink:to="loc_paa_BusinessAcquisitionProFormaNetIncomeLossAllocatedToCommonUnitholdersBasic_90c6f5e4-51fd-4056-bbc5-7aa8f1a46a82" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionProFormaEarningsPerShareBasic_f19a2d7d-22da-4d9e-a414-2013b374e6ef" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionProFormaEarningsPerShareBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_f7004a7c-de91-4161-b5d1-1602b92ae53d" xlink:to="loc_us-gaap_BusinessAcquisitionProFormaEarningsPerShareBasic_f19a2d7d-22da-4d9e-a414-2013b374e6ef" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionProFormaEarningsPerShareDiluted_b06641aa-ebbd-420d-bfbd-ec1a4d2e64e7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionProFormaEarningsPerShareDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_f7004a7c-de91-4161-b5d1-1602b92ae53d" xlink:to="loc_us-gaap_BusinessAcquisitionProFormaEarningsPerShareDiluted_b06641aa-ebbd-420d-bfbd-ec1a4d2e64e7" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_0511de0f-5a63-4007-95a1-991282f501f6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_f7004a7c-de91-4161-b5d1-1602b92ae53d" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_0511de0f-5a63-4007-95a1-991282f501f6" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_54c5e239-2150-47c2-afca-760240ede7f4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_0511de0f-5a63-4007-95a1-991282f501f6" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_54c5e239-2150-47c2-afca-760240ede7f4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_54c5e239-2150-47c2-afca-760240ede7f4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_54c5e239-2150-47c2-afca-760240ede7f4" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_54c5e239-2150-47c2-afca-760240ede7f4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_6434e7be-8e4c-42ea-a911-1e141778678d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_54c5e239-2150-47c2-afca-760240ede7f4" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_6434e7be-8e4c-42ea-a911-1e141778678d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PlainsOryxPermianBasinLLCMember_ea6bf6b2-34e2-4237-aaf9-fe262c9606f6" xlink:href="paa-20211231.xsd#paa_PlainsOryxPermianBasinLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_6434e7be-8e4c-42ea-a911-1e141778678d" xlink:to="loc_paa_PlainsOryxPermianBasinLLCMember_ea6bf6b2-34e2-4237-aaf9-fe262c9606f6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_6f6ebfc2-8831-4841-88a6-f87e66705bba" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_0511de0f-5a63-4007-95a1-991282f501f6" xlink:to="loc_srt_CounterpartyNameAxis_6f6ebfc2-8831-4841-88a6-f87e66705bba" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_6f6ebfc2-8831-4841-88a6-f87e66705bba_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_6f6ebfc2-8831-4841-88a6-f87e66705bba" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_6f6ebfc2-8831-4841-88a6-f87e66705bba_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_1e0ea3bb-f9a7-4442-8817-65e9a36854bf" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_6f6ebfc2-8831-4841-88a6-f87e66705bba" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_1e0ea3bb-f9a7-4442-8817-65e9a36854bf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_OryxMidstreamHoldingsLLCMember_a21bad70-fed1-4b39-b624-ed66ff92f754" xlink:href="paa-20211231.xsd#paa_OryxMidstreamHoldingsLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_1e0ea3bb-f9a7-4442-8817-65e9a36854bf" xlink:to="loc_paa_OryxMidstreamHoldingsLLCMember_a21bad70-fed1-4b39-b624-ed66ff92f754" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransactionTypeAxis_8630c8ff-9bc7-4363-9a2f-8fc05b562686" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransactionTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_0511de0f-5a63-4007-95a1-991282f501f6" xlink:to="loc_us-gaap_TransactionTypeAxis_8630c8ff-9bc7-4363-9a2f-8fc05b562686" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransactionDomain_8630c8ff-9bc7-4363-9a2f-8fc05b562686_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TransactionTypeAxis_8630c8ff-9bc7-4363-9a2f-8fc05b562686" xlink:to="loc_us-gaap_TransactionDomain_8630c8ff-9bc7-4363-9a2f-8fc05b562686_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransactionDomain_5fa958de-bb13-4d34-8966-24ca743ed26f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TransactionTypeAxis_8630c8ff-9bc7-4363-9a2f-8fc05b562686" xlink:to="loc_us-gaap_TransactionDomain_5fa958de-bb13-4d34-8966-24ca743ed26f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_JointVentureFormationMember_b7c12136-77fa-4a75-b9de-a55e47e538a5" xlink:href="paa-20211231.xsd#paa_JointVentureFormationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransactionDomain_5fa958de-bb13-4d34-8966-24ca743ed26f" xlink:to="loc_paa_JointVentureFormationMember_b7c12136-77fa-4a75-b9de-a55e47e538a5" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/AcquisitionsDivestituresandOtherTransactionsAssetExchangeDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#AcquisitionsDivestituresandOtherTransactionsAssetExchangeDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/AcquisitionsDivestituresandOtherTransactionsAssetExchangeDetails" xlink:type="extended" id="iff7853ea814746fa94cd5141a1a6421e_AcquisitionsDivestituresandOtherTransactionsAssetExchangeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_c9c677c3-4ef8-4aa8-9475-35c05ec3db77" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_NumberOfStraddlePlantsAdditionalInterestsAcquired_2a0c5270-f3d2-455f-a7c8-0a7bce8c860b" xlink:href="paa-20211231.xsd#paa_NumberOfStraddlePlantsAdditionalInterestsAcquired"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_c9c677c3-4ef8-4aa8-9475-35c05ec3db77" xlink:to="loc_paa_NumberOfStraddlePlantsAdditionalInterestsAcquired_2a0c5270-f3d2-455f-a7c8-0a7bce8c860b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireBusinessesGross_0f685d89-aae1-4630-80cf-59ccec567f3d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_c9c677c3-4ef8-4aa8-9475-35c05ec3db77" xlink:to="loc_us-gaap_PaymentsToAcquireBusinessesGross_0f685d89-aae1-4630-80cf-59ccec567f3d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnSalesOfAssetsAndAssetImpairmentCharges_01bb9d5a-77f2-4fc7-8986-2e76b1b35ccd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GainLossOnSalesOfAssetsAndAssetImpairmentCharges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_c9c677c3-4ef8-4aa8-9475-35c05ec3db77" xlink:to="loc_us-gaap_GainLossOnSalesOfAssetsAndAssetImpairmentCharges_01bb9d5a-77f2-4fc7-8986-2e76b1b35ccd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_e98c7ce8-843a-42e5-b501-21f2126215b0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_c9c677c3-4ef8-4aa8-9475-35c05ec3db77" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_e98c7ce8-843a-42e5-b501-21f2126215b0" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_6c9cbec3-bc48-4603-9029-b4ef9a37362d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_e98c7ce8-843a-42e5-b501-21f2126215b0" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_6c9cbec3-bc48-4603-9029-b4ef9a37362d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_6c9cbec3-bc48-4603-9029-b4ef9a37362d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_6c9cbec3-bc48-4603-9029-b4ef9a37362d" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_6c9cbec3-bc48-4603-9029-b4ef9a37362d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_2958005a-6d9e-4152-af5d-a78493a8e2dd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_6c9cbec3-bc48-4603-9029-b4ef9a37362d" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_2958005a-6d9e-4152-af5d-a78493a8e2dd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_AdditionalInterestsInStraddlePlantsMember_24da45ba-40ef-4b0f-a12d-0138372ef3ab" xlink:href="paa-20211231.xsd#paa_AdditionalInterestsInStraddlePlantsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_2958005a-6d9e-4152-af5d-a78493a8e2dd" xlink:to="loc_paa_AdditionalInterestsInStraddlePlantsMember_24da45ba-40ef-4b0f-a12d-0138372ef3ab" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_674f1151-9734-42b8-92bd-366d337d4a36" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_e98c7ce8-843a-42e5-b501-21f2126215b0" xlink:to="loc_srt_CounterpartyNameAxis_674f1151-9734-42b8-92bd-366d337d4a36" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_674f1151-9734-42b8-92bd-366d337d4a36_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_674f1151-9734-42b8-92bd-366d337d4a36" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_674f1151-9734-42b8-92bd-366d337d4a36_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_612d78ed-54f9-49d1-8fc4-43afa92becff" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_674f1151-9734-42b8-92bd-366d337d4a36" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_612d78ed-54f9-49d1-8fc4-43afa92becff" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_InterPipelineLtdMember_8ee7d504-439d-4bee-97ff-a34aa3c8db3e" xlink:href="paa-20211231.xsd#paa_InterPipelineLtdMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_612d78ed-54f9-49d1-8fc4-43afa92becff" xlink:to="loc_paa_InterPipelineLtdMember_8ee7d504-439d-4bee-97ff-a34aa3c8db3e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_d7987c0a-d7ef-4336-bb4d-33d78f811d62" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_e98c7ce8-843a-42e5-b501-21f2126215b0" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_d7987c0a-d7ef-4336-bb4d-33d78f811d62" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_d7987c0a-d7ef-4336-bb4d-33d78f811d62_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_d7987c0a-d7ef-4336-bb4d-33d78f811d62" xlink:to="loc_us-gaap_SegmentDomain_d7987c0a-d7ef-4336-bb4d-33d78f811d62_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_391b4367-3e21-49f8-b89a-1d8762f7ed5d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_d7987c0a-d7ef-4336-bb4d-33d78f811d62" xlink:to="loc_us-gaap_SegmentDomain_391b4367-3e21-49f8-b89a-1d8762f7ed5d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_NaturalGasLiquidsSegmentMember_05251846-cc0a-4386-939d-e2868968cc79" xlink:href="paa-20211231.xsd#paa_NaturalGasLiquidsSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_391b4367-3e21-49f8-b89a-1d8762f7ed5d" xlink:to="loc_paa_NaturalGasLiquidsSegmentMember_05251846-cc0a-4386-939d-e2868968cc79" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransactionTypeAxis_d051b079-862d-4c09-9a2e-8f352a6bdacf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransactionTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_e98c7ce8-843a-42e5-b501-21f2126215b0" xlink:to="loc_us-gaap_TransactionTypeAxis_d051b079-862d-4c09-9a2e-8f352a6bdacf" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransactionDomain_d051b079-862d-4c09-9a2e-8f352a6bdacf_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TransactionTypeAxis_d051b079-862d-4c09-9a2e-8f352a6bdacf" xlink:to="loc_us-gaap_TransactionDomain_d051b079-862d-4c09-9a2e-8f352a6bdacf_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransactionDomain_29bb4003-4946-457d-bcdc-e2ed67cb849d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TransactionTypeAxis_d051b079-862d-4c09-9a2e-8f352a6bdacf" xlink:to="loc_us-gaap_TransactionDomain_29bb4003-4946-457d-bcdc-e2ed67cb849d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_AssetExchangeTransactionMember_eeb1d3b6-3bed-4101-8882-5a2f6e055158" xlink:href="paa-20211231.xsd#paa_AssetExchangeTransactionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransactionDomain_29bb4003-4946-457d-bcdc-e2ed67cb849d" xlink:to="loc_paa_AssetExchangeTransactionMember_eeb1d3b6-3bed-4101-8882-5a2f6e055158" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_3491463b-ce5c-4b8b-9a15-7364744f5e2e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_e98c7ce8-843a-42e5-b501-21f2126215b0" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_3491463b-ce5c-4b8b-9a15-7364744f5e2e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_3491463b-ce5c-4b8b-9a15-7364744f5e2e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_3491463b-ce5c-4b8b-9a15-7364744f5e2e" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_3491463b-ce5c-4b8b-9a15-7364744f5e2e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_375a3988-8410-4663-b226-1a5375ca6430" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_3491463b-ce5c-4b8b-9a15-7364744f5e2e" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_375a3988-8410-4663-b226-1a5375ca6430" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_GainsLossesOnAssetSalesAndAssetImpairmentsNetMember_2b290e28-e437-41c8-acf5-621e551ca5b4" xlink:href="paa-20211231.xsd#paa_GainsLossesOnAssetSalesAndAssetImpairmentsNetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_375a3988-8410-4663-b226-1a5375ca6430" xlink:to="loc_paa_GainsLossesOnAssetSalesAndAssetImpairmentsNetMember_2b290e28-e437-41c8-acf5-621e551ca5b4" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/AcquisitionsDivestituresandOtherTransactionsAcquisitionsDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#AcquisitionsDivestituresandOtherTransactionsAcquisitionsDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/AcquisitionsDivestituresandOtherTransactionsAcquisitionsDetails" xlink:type="extended" id="i8cefa9cd489d4145bd967ae4f312a33d_AcquisitionsDivestituresandOtherTransactionsAcquisitionsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_d3dc45ee-a621-42f9-83ab-3566cd7becec" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireBusinessesAndInterestInAffiliates_dfdbf553-a47a-4795-8e71-3fdd19c48dc9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesAndInterestInAffiliates"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_d3dc45ee-a621-42f9-83ab-3566cd7becec" xlink:to="loc_us-gaap_PaymentsToAcquireBusinessesAndInterestInAffiliates_dfdbf553-a47a-4795-8e71-3fdd19c48dc9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment_34bed95b-c0b4-4859-a4c9-3ee2dd4fc859" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_d3dc45ee-a621-42f9-83ab-3566cd7becec" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment_34bed95b-c0b4-4859-a4c9-3ee2dd4fc859" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill_5a263e47-3852-49f7-b689-bf264446ccf3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_d3dc45ee-a621-42f9-83ab-3566cd7becec" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill_5a263e47-3852-49f7-b689-bf264446ccf3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_BusinessCombinationMeasurementInput_e136cc89-4c22-4197-882f-11651a900d37" xlink:href="paa-20211231.xsd#paa_BusinessCombinationMeasurementInput"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_d3dc45ee-a621-42f9-83ab-3566cd7becec" xlink:to="loc_paa_BusinessCombinationMeasurementInput_e136cc89-4c22-4197-882f-11651a900d37" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireProductiveAssets_4a43e0cb-e100-456f-9f46-2ce18d6ab69e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentsToAcquireProductiveAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_d3dc45ee-a621-42f9-83ab-3566cd7becec" xlink:to="loc_us-gaap_PaymentsToAcquireProductiveAssets_4a43e0cb-e100-456f-9f46-2ce18d6ab69e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_2d3708c3-8eec-4bd1-81d3-2af2c2c61259" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_d3dc45ee-a621-42f9-83ab-3566cd7becec" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_2d3708c3-8eec-4bd1-81d3-2af2c2c61259" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_56bd262c-f02c-413e-9932-1bc7d49a85d7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_2d3708c3-8eec-4bd1-81d3-2af2c2c61259" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_56bd262c-f02c-413e-9932-1bc7d49a85d7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_56bd262c-f02c-413e-9932-1bc7d49a85d7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_56bd262c-f02c-413e-9932-1bc7d49a85d7" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_56bd262c-f02c-413e-9932-1bc7d49a85d7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_1c9c496f-f8ad-47a6-8ea9-65ca1c7e3eb1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_56bd262c-f02c-413e-9932-1bc7d49a85d7" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_1c9c496f-f8ad-47a6-8ea9-65ca1c7e3eb1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_FMGatheringLLCMember_13a8c230-a551-4408-a26f-ccaf32c0b815" xlink:href="paa-20211231.xsd#paa_FMGatheringLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_1c9c496f-f8ad-47a6-8ea9-65ca1c7e3eb1" xlink:to="loc_paa_FMGatheringLLCMember_13a8c230-a551-4408-a26f-ccaf32c0b815" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_9fdedfe9-d17e-4675-962c-3158278d3996" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_2d3708c3-8eec-4bd1-81d3-2af2c2c61259" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_9fdedfe9-d17e-4675-962c-3158278d3996" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_9fdedfe9-d17e-4675-962c-3158278d3996_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_9fdedfe9-d17e-4675-962c-3158278d3996" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_9fdedfe9-d17e-4675-962c-3158278d3996_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_edc2c819-f2ed-4e17-8ab0-0613f07d9629" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_9fdedfe9-d17e-4675-962c-3158278d3996" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_edc2c819-f2ed-4e17-8ab0-0613f07d9629" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_CrudeOilTerminalMember_42c450bb-4c64-4b9a-941e-b95a5193d18d" xlink:href="paa-20211231.xsd#paa_CrudeOilTerminalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_edc2c819-f2ed-4e17-8ab0-0613f07d9629" xlink:to="loc_paa_CrudeOilTerminalMember_42c450bb-4c64-4b9a-941e-b95a5193d18d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_ad1b0d07-13db-44a6-8641-5b6fc04d49e1" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_2d3708c3-8eec-4bd1-81d3-2af2c2c61259" xlink:to="loc_srt_RangeAxis_ad1b0d07-13db-44a6-8641-5b6fc04d49e1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_ad1b0d07-13db-44a6-8641-5b6fc04d49e1_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_ad1b0d07-13db-44a6-8641-5b6fc04d49e1" xlink:to="loc_srt_RangeMember_ad1b0d07-13db-44a6-8641-5b6fc04d49e1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_18c0f641-f72a-4bcb-87a6-ad693aa54799" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_ad1b0d07-13db-44a6-8641-5b6fc04d49e1" xlink:to="loc_srt_RangeMember_18c0f641-f72a-4bcb-87a6-ad693aa54799" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_c640205c-bdbf-4f6b-ba8e-b8d8cdd2881d" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_18c0f641-f72a-4bcb-87a6-ad693aa54799" xlink:to="loc_srt_MinimumMember_c640205c-bdbf-4f6b-ba8e-b8d8cdd2881d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_14bffc4c-a73e-405c-800e-407435ceaa46" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_18c0f641-f72a-4bcb-87a6-ad693aa54799" xlink:to="loc_srt_MaximumMember_14bffc4c-a73e-405c-800e-407435ceaa46" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_b6fb0345-32db-4946-b235-8d70b1bd832f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_2d3708c3-8eec-4bd1-81d3-2af2c2c61259" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_b6fb0345-32db-4946-b235-8d70b1bd832f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_b6fb0345-32db-4946-b235-8d70b1bd832f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_b6fb0345-32db-4946-b235-8d70b1bd832f" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_b6fb0345-32db-4946-b235-8d70b1bd832f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_92a8ae22-37e3-4dc9-8f17-96f29a4d40d9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_b6fb0345-32db-4946-b235-8d70b1bd832f" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_92a8ae22-37e3-4dc9-8f17-96f29a4d40d9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_220915c5-1066-46c6-9484-639a304ab781" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_92a8ae22-37e3-4dc9-8f17-96f29a4d40d9" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_220915c5-1066-46c6-9484-639a304ab781" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeAxis_73e173cb-3702-4ca6-95fa-b54d438b42ae" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MeasurementInputTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_2d3708c3-8eec-4bd1-81d3-2af2c2c61259" xlink:to="loc_us-gaap_MeasurementInputTypeAxis_73e173cb-3702-4ca6-95fa-b54d438b42ae" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_73e173cb-3702-4ca6-95fa-b54d438b42ae_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_73e173cb-3702-4ca6-95fa-b54d438b42ae" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_73e173cb-3702-4ca6-95fa-b54d438b42ae_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_51f42729-e200-4921-ad6c-9d88f9123b4c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_73e173cb-3702-4ca6-95fa-b54d438b42ae" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_51f42729-e200-4921-ad6c-9d88f9123b4c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputDiscountRateMember_3c0855aa-1d76-4dc7-af7a-bf98998e7750" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MeasurementInputDiscountRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_51f42729-e200-4921-ad6c-9d88f9123b4c" xlink:to="loc_us-gaap_MeasurementInputDiscountRateMember_3c0855aa-1d76-4dc7-af7a-bf98998e7750" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationTechniqueAxis_b499b12e-4b68-4e11-a811-782f6044d731" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ValuationTechniqueAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_2d3708c3-8eec-4bd1-81d3-2af2c2c61259" xlink:to="loc_us-gaap_ValuationTechniqueAxis_b499b12e-4b68-4e11-a811-782f6044d731" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationTechniqueDomain_b499b12e-4b68-4e11-a811-782f6044d731_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ValuationTechniqueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ValuationTechniqueAxis_b499b12e-4b68-4e11-a811-782f6044d731" xlink:to="loc_us-gaap_ValuationTechniqueDomain_b499b12e-4b68-4e11-a811-782f6044d731_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationTechniqueDomain_004e6e9e-ce0e-4b07-829c-e0d87800241f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ValuationTechniqueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ValuationTechniqueAxis_b499b12e-4b68-4e11-a811-782f6044d731" xlink:to="loc_us-gaap_ValuationTechniqueDomain_004e6e9e-ce0e-4b07-829c-e0d87800241f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationTechniqueDiscountedCashFlowMember_6360879e-a267-40ee-b4d5-6a39df282989" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ValuationTechniqueDiscountedCashFlowMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationTechniqueDomain_004e6e9e-ce0e-4b07-829c-e0d87800241f" xlink:to="loc_us-gaap_ValuationTechniqueDiscountedCashFlowMember_6360879e-a267-40ee-b4d5-6a39df282989" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByAssetClassAxis_9ea35999-5fbf-4b54-a7c9-fbcd14ff5d5a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByAssetClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_2d3708c3-8eec-4bd1-81d3-2af2c2c61259" xlink:to="loc_us-gaap_FairValueByAssetClassAxis_9ea35999-5fbf-4b54-a7c9-fbcd14ff5d5a" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_9ea35999-5fbf-4b54-a7c9-fbcd14ff5d5a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByAssetClassAxis_9ea35999-5fbf-4b54-a7c9-fbcd14ff5d5a" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_9ea35999-5fbf-4b54-a7c9-fbcd14ff5d5a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_432d43ce-ddac-4c4c-a41d-458d3a71757b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByAssetClassAxis_9ea35999-5fbf-4b54-a7c9-fbcd14ff5d5a" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_432d43ce-ddac-4c4c-a41d-458d3a71757b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMember_2aba55b1-eeba-4416-8c22-cb2c5d1128c0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_432d43ce-ddac-4c4c-a41d-458d3a71757b" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMember_2aba55b1-eeba-4416-8c22-cb2c5d1128c0" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/AcquisitionsDivestituresandOtherTransactionsDivestituresDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#AcquisitionsDivestituresandOtherTransactionsDivestituresDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/AcquisitionsDivestituresandOtherTransactionsDivestituresDetails" xlink:type="extended" id="i8c67f74a0319478c935d416de20cd5b3_AcquisitionsDivestituresandOtherTransactionsDivestituresDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_f1ab97aa-fb5b-4a13-80e8-65a0896f96f2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromSaleOfProductiveAssets_d60c087e-e650-4c4f-86c7-703022fa11fe" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromSaleOfProductiveAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_f1ab97aa-fb5b-4a13-80e8-65a0896f96f2" xlink:to="loc_us-gaap_ProceedsFromSaleOfProductiveAssets_d60c087e-e650-4c4f-86c7-703022fa11fe" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationCurrent_f602ab5a-cfe8-4919-9a1c-4fe2abcb6924" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_f1ab97aa-fb5b-4a13-80e8-65a0896f96f2" xlink:to="loc_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationCurrent_f602ab5a-cfe8-4919-9a1c-4fe2abcb6924" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapital_7ddf6db4-a22c-4527-9c71-a6342d19289d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnersCapital"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_f1ab97aa-fb5b-4a13-80e8-65a0896f96f2" xlink:to="loc_us-gaap_PartnersCapital_7ddf6db4-a22c-4527-9c71-a6342d19289d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairmentOfLongLivedAssetsToBeDisposedOf_487a1199-24c6-416d-baec-245601eac4eb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ImpairmentOfLongLivedAssetsToBeDisposedOf"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_f1ab97aa-fb5b-4a13-80e8-65a0896f96f2" xlink:to="loc_us-gaap_ImpairmentOfLongLivedAssetsToBeDisposedOf_487a1199-24c6-416d-baec-245601eac4eb" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_ProceedsFromSaleOfProductiveAssetsAndAgreements_15cf4351-39f6-4b45-bb1a-86f3e5a4d82e" xlink:href="paa-20211231.xsd#paa_ProceedsFromSaleOfProductiveAssetsAndAgreements"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_f1ab97aa-fb5b-4a13-80e8-65a0896f96f2" xlink:to="loc_paa_ProceedsFromSaleOfProductiveAssetsAndAgreements_15cf4351-39f6-4b45-bb1a-86f3e5a4d82e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInDeferredRevenue_f1eeae37-d355-42ae-bad5-aee2463abf6d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInDeferredRevenue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_f1ab97aa-fb5b-4a13-80e8-65a0896f96f2" xlink:to="loc_us-gaap_IncreaseDecreaseInDeferredRevenue_f1eeae37-d355-42ae-bad5-aee2463abf6d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_EquityMethodInvestmentOwnershipPercentageSold_ea900d33-bc68-4619-9bfe-6d20517ef4f0" xlink:href="paa-20211231.xsd#paa_EquityMethodInvestmentOwnershipPercentageSold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_f1ab97aa-fb5b-4a13-80e8-65a0896f96f2" xlink:to="loc_paa_EquityMethodInvestmentOwnershipPercentageSold_ea900d33-bc68-4619-9bfe-6d20517ef4f0" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromSaleOfEquityMethodInvestments_9b6ce81f-0c07-4199-92f5-5f32f4cdc9cc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromSaleOfEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_f1ab97aa-fb5b-4a13-80e8-65a0896f96f2" xlink:to="loc_us-gaap_ProceedsFromSaleOfEquityMethodInvestments_9b6ce81f-0c07-4199-92f5-5f32f4cdc9cc" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnSalesOfAssetsAndAssetImpairmentCharges_c82701a5-896c-4ad0-8f77-8fcb4a84a4f4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GainLossOnSalesOfAssetsAndAssetImpairmentCharges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_f1ab97aa-fb5b-4a13-80e8-65a0896f96f2" xlink:to="loc_us-gaap_GainLossOnSalesOfAssetsAndAssetImpairmentCharges_c82701a5-896c-4ad0-8f77-8fcb4a84a4f4" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnDispositionOfAssets1_02ec3a85-bc8e-413b-8eae-b15904075c36" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GainLossOnDispositionOfAssets1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_f1ab97aa-fb5b-4a13-80e8-65a0896f96f2" xlink:to="loc_us-gaap_GainLossOnDispositionOfAssets1_02ec3a85-bc8e-413b-8eae-b15904075c36" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_GainOnDispositionOfAssets_9bc82829-1d1b-4c4c-9aa0-91b2c47567b3" xlink:href="paa-20211231.xsd#paa_GainOnDispositionOfAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_f1ab97aa-fb5b-4a13-80e8-65a0896f96f2" xlink:to="loc_paa_GainOnDispositionOfAssets_9bc82829-1d1b-4c4c-9aa0-91b2c47567b3" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_LossOnDispositionOfAssets_42a321b8-ce0d-4a14-ac63-bc39ba3b970f" xlink:href="paa-20211231.xsd#paa_LossOnDispositionOfAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_f1ab97aa-fb5b-4a13-80e8-65a0896f96f2" xlink:to="loc_paa_LossOnDispositionOfAssets_42a321b8-ce0d-4a14-ac63-bc39ba3b970f" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_621f1e44-4b2d-4eef-8559-1cf3b6782a5e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_f1ab97aa-fb5b-4a13-80e8-65a0896f96f2" xlink:to="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_621f1e44-4b2d-4eef-8559-1cf3b6782a5e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerCapitalComponentsAxis_ef99305b-92ab-4885-9d99-7662497185f1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnerCapitalComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_621f1e44-4b2d-4eef-8559-1cf3b6782a5e" xlink:to="loc_us-gaap_PartnerCapitalComponentsAxis_ef99305b-92ab-4885-9d99-7662497185f1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerCapitalComponentsDomain_ef99305b-92ab-4885-9d99-7662497185f1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnerCapitalComponentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PartnerCapitalComponentsAxis_ef99305b-92ab-4885-9d99-7662497185f1" xlink:to="loc_us-gaap_PartnerCapitalComponentsDomain_ef99305b-92ab-4885-9d99-7662497185f1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerCapitalComponentsDomain_0cb33070-9602-4665-a0ae-f200dcf3fef7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnerCapitalComponentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PartnerCapitalComponentsAxis_ef99305b-92ab-4885-9d99-7662497185f1" xlink:to="loc_us-gaap_PartnerCapitalComponentsDomain_0cb33070-9602-4665-a0ae-f200dcf3fef7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedGainLossCashFlowHedgeIncludingNoncontrollingInterestMember_bc2ca78c-0ef8-490d-adda-812c654dc457" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedGainLossCashFlowHedgeIncludingNoncontrollingInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnerCapitalComponentsDomain_0cb33070-9602-4665-a0ae-f200dcf3fef7" xlink:to="loc_us-gaap_AccumulatedGainLossCashFlowHedgeIncludingNoncontrollingInterestMember_bc2ca78c-0ef8-490d-adda-812c654dc457" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_743f24c7-5f8b-47ed-a750-b783a843c5ec" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_621f1e44-4b2d-4eef-8559-1cf3b6782a5e" xlink:to="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_743f24c7-5f8b-47ed-a750-b783a843c5ec" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_743f24c7-5f8b-47ed-a750-b783a843c5ec_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_743f24c7-5f8b-47ed-a750-b783a843c5ec" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_743f24c7-5f8b-47ed-a750-b783a843c5ec_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_9c8e860f-6ca1-4bf4-ae1a-bd2e8d25d134" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_743f24c7-5f8b-47ed-a750-b783a843c5ec" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_9c8e860f-6ca1-4bf4-ae1a-bd2e8d25d134" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SaddlehornPipelineCompanyLLCMember_f3dec3b9-c000-421e-a319-dc0b341b2462" xlink:href="paa-20211231.xsd#paa_SaddlehornPipelineCompanyLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_9c8e860f-6ca1-4bf4-ae1a-bd2e8d25d134" xlink:to="loc_paa_SaddlehornPipelineCompanyLLCMember_f3dec3b9-c000-421e-a319-dc0b341b2462" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_1ba0e404-8475-4617-9a39-c9202e3a5c9e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_621f1e44-4b2d-4eef-8559-1cf3b6782a5e" xlink:to="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_1ba0e404-8475-4617-9a39-c9202e3a5c9e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_1ba0e404-8475-4617-9a39-c9202e3a5c9e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_1ba0e404-8475-4617-9a39-c9202e3a5c9e" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_1ba0e404-8475-4617-9a39-c9202e3a5c9e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_a3c46d80-001d-4672-ac4b-154a8ddf0e09" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_1ba0e404-8475-4617-9a39-c9202e3a5c9e" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_a3c46d80-001d-4672-ac4b-154a8ddf0e09" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PinePrairieAndSouthernPinesNaturalGasStorageFacilitiesMember_fd96b68e-e8d9-4e31-be25-b5b30fe79240" xlink:href="paa-20211231.xsd#paa_PinePrairieAndSouthernPinesNaturalGasStorageFacilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_a3c46d80-001d-4672-ac4b-154a8ddf0e09" xlink:to="loc_paa_PinePrairieAndSouthernPinesNaturalGasStorageFacilitiesMember_fd96b68e-e8d9-4e31-be25-b5b30fe79240" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_LosAngelesBasinCrudeOilTerminalsMember_208f9c3c-f42d-4c3e-b6c7-fc84a10e2bba" xlink:href="paa-20211231.xsd#paa_LosAngelesBasinCrudeOilTerminalsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_a3c46d80-001d-4672-ac4b-154a8ddf0e09" xlink:to="loc_paa_LosAngelesBasinCrudeOilTerminalsMember_208f9c3c-f42d-4c3e-b6c7-fc84a10e2bba" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_NGLTerminalsMember_e3c68003-a18d-476f-a5d1-74ec42a107d4" xlink:href="paa-20211231.xsd#paa_NGLTerminalsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_a3c46d80-001d-4672-ac4b-154a8ddf0e09" xlink:to="loc_paa_NGLTerminalsMember_e3c68003-a18d-476f-a5d1-74ec42a107d4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_NorthDakotaStorageTerminalsMember_6fd8a456-e30a-4e8f-81c3-6516b4343326" xlink:href="paa-20211231.xsd#paa_NorthDakotaStorageTerminalsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_a3c46d80-001d-4672-ac4b-154a8ddf0e09" xlink:to="loc_paa_NorthDakotaStorageTerminalsMember_6fd8a456-e30a-4e8f-81c3-6516b4343326" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationAxis_b0138454-d7cc-4b04-87cb-c374449c89e9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisposalGroupClassificationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_621f1e44-4b2d-4eef-8559-1cf3b6782a5e" xlink:to="loc_us-gaap_DisposalGroupClassificationAxis_b0138454-d7cc-4b04-87cb-c374449c89e9" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_b0138454-d7cc-4b04-87cb-c374449c89e9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisposalGroupClassificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_b0138454-d7cc-4b04-87cb-c374449c89e9" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_b0138454-d7cc-4b04-87cb-c374449c89e9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_1a966ed5-857d-45a7-9cee-f4e27b4a8225" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisposalGroupClassificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_b0138454-d7cc-4b04-87cb-c374449c89e9" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_1a966ed5-857d-45a7-9cee-f4e27b4a8225" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupHeldforsaleNotDiscontinuedOperationsMember_5a586819-459e-49cf-abc5-cb8e38349452" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisposalGroupHeldforsaleNotDiscontinuedOperationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupClassificationDomain_1a966ed5-857d-45a7-9cee-f4e27b4a8225" xlink:to="loc_us-gaap_DisposalGroupHeldforsaleNotDiscontinuedOperationsMember_5a586819-459e-49cf-abc5-cb8e38349452" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember_da5ee1d5-8be6-4217-a552-f9ccea50dafd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupClassificationDomain_1a966ed5-857d-45a7-9cee-f4e27b4a8225" xlink:to="loc_us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember_da5ee1d5-8be6-4217-a552-f9ccea50dafd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_d67f4127-84f6-49a1-bf08-ccb1830bb268" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_621f1e44-4b2d-4eef-8559-1cf3b6782a5e" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_d67f4127-84f6-49a1-bf08-ccb1830bb268" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_d67f4127-84f6-49a1-bf08-ccb1830bb268_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_d67f4127-84f6-49a1-bf08-ccb1830bb268" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_d67f4127-84f6-49a1-bf08-ccb1830bb268_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_8fe89f35-d77e-4e1a-9955-06a5aec63036" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_d67f4127-84f6-49a1-bf08-ccb1830bb268" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_8fe89f35-d77e-4e1a-9955-06a5aec63036" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_GainsLossesOnAssetSalesAndAssetImpairmentsNetMember_0efab2b9-b99c-4b0c-8c9e-9996711c2631" xlink:href="paa-20211231.xsd#paa_GainsLossesOnAssetSalesAndAssetImpairmentsNetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_8fe89f35-d77e-4e1a-9955-06a5aec63036" xlink:to="loc_paa_GainsLossesOnAssetSalesAndAssetImpairmentsNetMember_0efab2b9-b99c-4b0c-8c9e-9996711c2631" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_dbb8f890-dfae-4cd8-a797-1b0bd5b76e60" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_621f1e44-4b2d-4eef-8559-1cf3b6782a5e" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_dbb8f890-dfae-4cd8-a797-1b0bd5b76e60" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_dbb8f890-dfae-4cd8-a797-1b0bd5b76e60_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_dbb8f890-dfae-4cd8-a797-1b0bd5b76e60" xlink:to="loc_us-gaap_SegmentDomain_dbb8f890-dfae-4cd8-a797-1b0bd5b76e60_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_c0b6e618-0466-4798-bbec-e1f91b344f62" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_dbb8f890-dfae-4cd8-a797-1b0bd5b76e60" xlink:to="loc_us-gaap_SegmentDomain_c0b6e618-0466-4798-bbec-e1f91b344f62" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_CrudeOilSegmentMember_e4508a0a-570d-453f-bdd2-b9d8bee096f3" xlink:href="paa-20211231.xsd#paa_CrudeOilSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_c0b6e618-0466-4798-bbec-e1f91b344f62" xlink:to="loc_paa_CrudeOilSegmentMember_e4508a0a-570d-453f-bdd2-b9d8bee096f3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_NaturalGasLiquidsSegmentMember_6a2e021f-b2e2-40ed-8965-135cba2b3be9" xlink:href="paa-20211231.xsd#paa_NaturalGasLiquidsSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_c0b6e618-0466-4798-bbec-e1f91b344f62" xlink:to="loc_paa_NaturalGasLiquidsSegmentMember_6a2e021f-b2e2-40ed-8965-135cba2b3be9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_a63ef849-d2f6-46b8-b42d-9abe50ad3d5f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_621f1e44-4b2d-4eef-8559-1cf3b6782a5e" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_a63ef849-d2f6-46b8-b42d-9abe50ad3d5f" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_a63ef849-d2f6-46b8-b42d-9abe50ad3d5f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_a63ef849-d2f6-46b8-b42d-9abe50ad3d5f" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_a63ef849-d2f6-46b8-b42d-9abe50ad3d5f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_c5e60aef-f21d-4def-b0f6-a5d6fab52225" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_a63ef849-d2f6-46b8-b42d-9abe50ad3d5f" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_c5e60aef-f21d-4def-b0f6-a5d6fab52225" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NaturalGasStorageMember_36fb80d6-2952-49c1-86d1-33c2bac192ad" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NaturalGasStorageMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_c5e60aef-f21d-4def-b0f6-a5d6fab52225" xlink:to="loc_us-gaap_NaturalGasStorageMember_36fb80d6-2952-49c1-86d1-33c2bac192ad" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/GoodwillDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#GoodwillDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/GoodwillDetails" xlink:type="extended" id="i69e7863aafa74c18bc779302570b7c91_GoodwillDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillLineItems_a2466b82-32e7-4a6f-bd38-7e0af279a7b1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GoodwillLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_GoodwillImpairmentAnalysisCostOfCapitalTheoreticalMarketParticipant_5ff23337-5a61-41a1-8927-e7fa858b3302" xlink:href="paa-20211231.xsd#paa_GoodwillImpairmentAnalysisCostOfCapitalTheoreticalMarketParticipant"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_a2466b82-32e7-4a6f-bd38-7e0af279a7b1" xlink:to="loc_paa_GoodwillImpairmentAnalysisCostOfCapitalTheoreticalMarketParticipant_5ff23337-5a61-41a1-8927-e7fa858b3302" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_GoodwillImpairmentAnalysisProjectedCashFlowsPeriod_9d773cb1-6714-4d3f-ad5d-5589cbf010ad" xlink:href="paa-20211231.xsd#paa_GoodwillImpairmentAnalysisProjectedCashFlowsPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_a2466b82-32e7-4a6f-bd38-7e0af279a7b1" xlink:to="loc_paa_GoodwillImpairmentAnalysisProjectedCashFlowsPeriod_9d773cb1-6714-4d3f-ad5d-5589cbf010ad" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillRollForward_4f77cce7-6dcf-425f-ba23-b10aba2fcc23" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GoodwillRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_a2466b82-32e7-4a6f-bd38-7e0af279a7b1" xlink:to="loc_us-gaap_GoodwillRollForward_4f77cce7-6dcf-425f-ba23-b10aba2fcc23" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_b93d4507-1bc7-46fe-9c23-8b278645f0d2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillRollForward_4f77cce7-6dcf-425f-ba23-b10aba2fcc23" xlink:to="loc_us-gaap_Goodwill_b93d4507-1bc7-46fe-9c23-8b278645f0d2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillAcquiredDuringPeriod_eadb592a-976c-44fd-9b88-08b2470da2ae" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GoodwillAcquiredDuringPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillRollForward_4f77cce7-6dcf-425f-ba23-b10aba2fcc23" xlink:to="loc_us-gaap_GoodwillAcquiredDuringPeriod_eadb592a-976c-44fd-9b88-08b2470da2ae" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillGross_21b3dc36-7064-4610-a932-dc46613fe9ac" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GoodwillGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillRollForward_4f77cce7-6dcf-425f-ba23-b10aba2fcc23" xlink:to="loc_us-gaap_GoodwillGross_21b3dc36-7064-4610-a932-dc46613fe9ac" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillImpairmentLoss_e697777d-dcde-481c-9a26-f16540cd816f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GoodwillImpairmentLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillRollForward_4f77cce7-6dcf-425f-ba23-b10aba2fcc23" xlink:to="loc_us-gaap_GoodwillImpairmentLoss_e697777d-dcde-481c-9a26-f16540cd816f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_GoodwillAccumulatedImpairmentForeignCurrencyTranslationGainLoss_c6f19b54-42b6-419a-bd4a-ec686455291e" xlink:href="paa-20211231.xsd#paa_GoodwillAccumulatedImpairmentForeignCurrencyTranslationGainLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillRollForward_4f77cce7-6dcf-425f-ba23-b10aba2fcc23" xlink:to="loc_paa_GoodwillAccumulatedImpairmentForeignCurrencyTranslationGainLoss_c6f19b54-42b6-419a-bd4a-ec686455291e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillImpairedAccumulatedImpairmentLoss_8d7b6102-f1c2-4418-867e-c1bce959217d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GoodwillImpairedAccumulatedImpairmentLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillRollForward_4f77cce7-6dcf-425f-ba23-b10aba2fcc23" xlink:to="loc_us-gaap_GoodwillImpairedAccumulatedImpairmentLoss_8d7b6102-f1c2-4418-867e-c1bce959217d" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_0bc24154-ce37-43e9-b888-c07bc5613745" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Goodwill"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfGoodwillTable_92f620e9-2c0a-40fd-b949-467602b6dbbc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfGoodwillTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_GoodwillLineItems_a2466b82-32e7-4a6f-bd38-7e0af279a7b1" xlink:to="loc_us-gaap_ScheduleOfGoodwillTable_92f620e9-2c0a-40fd-b949-467602b6dbbc" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_dcfadc7f-9386-4fe2-b5a6-c97cec8dedd0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_92f620e9-2c0a-40fd-b949-467602b6dbbc" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_dcfadc7f-9386-4fe2-b5a6-c97cec8dedd0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_dcfadc7f-9386-4fe2-b5a6-c97cec8dedd0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_dcfadc7f-9386-4fe2-b5a6-c97cec8dedd0" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_dcfadc7f-9386-4fe2-b5a6-c97cec8dedd0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_c0c4c9e1-0fd9-45f2-9f32-c4f610a10054" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_dcfadc7f-9386-4fe2-b5a6-c97cec8dedd0" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_c0c4c9e1-0fd9-45f2-9f32-c4f610a10054" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_bbac3e9b-3a98-40b4-b3ad-0817ccd24575" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_c0c4c9e1-0fd9-45f2-9f32-c4f610a10054" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_bbac3e9b-3a98-40b4-b3ad-0817ccd24575" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationTechniqueAxis_709dbd05-891a-408e-85c2-046edb6b961b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ValuationTechniqueAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_92f620e9-2c0a-40fd-b949-467602b6dbbc" xlink:to="loc_us-gaap_ValuationTechniqueAxis_709dbd05-891a-408e-85c2-046edb6b961b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationTechniqueDomain_709dbd05-891a-408e-85c2-046edb6b961b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ValuationTechniqueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ValuationTechniqueAxis_709dbd05-891a-408e-85c2-046edb6b961b" xlink:to="loc_us-gaap_ValuationTechniqueDomain_709dbd05-891a-408e-85c2-046edb6b961b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationTechniqueDomain_10d431ad-e905-4751-a19d-69e1166f49ce" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ValuationTechniqueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ValuationTechniqueAxis_709dbd05-891a-408e-85c2-046edb6b961b" xlink:to="loc_us-gaap_ValuationTechniqueDomain_10d431ad-e905-4751-a19d-69e1166f49ce" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationTechniqueDiscountedCashFlowMember_04fde605-e8b9-4d8d-b8d9-0f074699707d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ValuationTechniqueDiscountedCashFlowMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationTechniqueDomain_10d431ad-e905-4751-a19d-69e1166f49ce" xlink:to="loc_us-gaap_ValuationTechniqueDiscountedCashFlowMember_04fde605-e8b9-4d8d-b8d9-0f074699707d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeAxis_a5ebc7b1-784e-4ca6-b89c-41f1c8fd27e6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MeasurementInputTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_92f620e9-2c0a-40fd-b949-467602b6dbbc" xlink:to="loc_us-gaap_MeasurementInputTypeAxis_a5ebc7b1-784e-4ca6-b89c-41f1c8fd27e6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_a5ebc7b1-784e-4ca6-b89c-41f1c8fd27e6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_a5ebc7b1-784e-4ca6-b89c-41f1c8fd27e6" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_a5ebc7b1-784e-4ca6-b89c-41f1c8fd27e6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_8140345d-e226-4468-ac51-064322dc6e21" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_a5ebc7b1-784e-4ca6-b89c-41f1c8fd27e6" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_8140345d-e226-4468-ac51-064322dc6e21" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputDiscountRateMember_6d98c4a2-54e6-41ce-8036-1792a07cc027" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MeasurementInputDiscountRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_8140345d-e226-4468-ac51-064322dc6e21" xlink:to="loc_us-gaap_MeasurementInputDiscountRateMember_6d98c4a2-54e6-41ce-8036-1792a07cc027" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_baf60ced-bdbd-42c8-8d5b-408ceaad4afc" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_92f620e9-2c0a-40fd-b949-467602b6dbbc" xlink:to="loc_srt_ConsolidationItemsAxis_baf60ced-bdbd-42c8-8d5b-408ceaad4afc" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_baf60ced-bdbd-42c8-8d5b-408ceaad4afc_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_baf60ced-bdbd-42c8-8d5b-408ceaad4afc" xlink:to="loc_srt_ConsolidationItemsDomain_baf60ced-bdbd-42c8-8d5b-408ceaad4afc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_7015d5e7-5636-43df-ae95-099822866b48" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_baf60ced-bdbd-42c8-8d5b-408ceaad4afc" xlink:to="loc_srt_ConsolidationItemsDomain_7015d5e7-5636-43df-ae95-099822866b48" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingSegmentsMember_43121896-578e-4e5e-ad99-d45fee6ff04e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_7015d5e7-5636-43df-ae95-099822866b48" xlink:to="loc_us-gaap_OperatingSegmentsMember_43121896-578e-4e5e-ad99-d45fee6ff04e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_7dbfcfbd-3545-441e-91e9-89628d170f9e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_92f620e9-2c0a-40fd-b949-467602b6dbbc" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_7dbfcfbd-3545-441e-91e9-89628d170f9e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_7dbfcfbd-3545-441e-91e9-89628d170f9e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_7dbfcfbd-3545-441e-91e9-89628d170f9e" xlink:to="loc_us-gaap_SegmentDomain_7dbfcfbd-3545-441e-91e9-89628d170f9e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_1c175b29-2642-4627-b7a1-9861436896ef" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_7dbfcfbd-3545-441e-91e9-89628d170f9e" xlink:to="loc_us-gaap_SegmentDomain_1c175b29-2642-4627-b7a1-9861436896ef" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_CrudeOilSegmentMember_1aba8c9b-8427-462c-8bb1-878f21d3121f" xlink:href="paa-20211231.xsd#paa_CrudeOilSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_1c175b29-2642-4627-b7a1-9861436896ef" xlink:to="loc_paa_CrudeOilSegmentMember_1aba8c9b-8427-462c-8bb1-878f21d3121f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_NaturalGasLiquidsSegmentMember_31e29f3a-4442-465b-91fd-d2b4068a8098" xlink:href="paa-20211231.xsd#paa_NaturalGasLiquidsSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_1c175b29-2642-4627-b7a1-9861436896ef" xlink:to="loc_paa_NaturalGasLiquidsSegmentMember_31e29f3a-4442-465b-91fd-d2b4068a8098" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/InvestmentsinUnconsolidatedEntitiesEquityMethodInvestmentsDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#InvestmentsinUnconsolidatedEntitiesEquityMethodInvestmentsDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/InvestmentsinUnconsolidatedEntitiesEquityMethodInvestmentsDetails" xlink:type="extended" id="ia4ede224b11a40a3be36d0d0332332b8_InvestmentsinUnconsolidatedEntitiesEquityMethodInvestmentsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_1433185f-d3d5-4069-92a7-bb0628409d18" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_c838aaad-3a1e-4917-91f9-7245269f6a86" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_1433185f-d3d5-4069-92a7-bb0628409d18" xlink:to="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_c838aaad-3a1e-4917-91f9-7245269f6a86" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestments_77af58f1-a503-4507-9a04-c7af9dc91161" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_1433185f-d3d5-4069-92a7-bb0628409d18" xlink:to="loc_us-gaap_EquityMethodInvestments_77af58f1-a503-4507-9a04-c7af9dc91161" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairmentOfInvestments_01d64efd-4d6f-4770-a225-73153fa6bdb2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ImpairmentOfInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_1433185f-d3d5-4069-92a7-bb0628409d18" xlink:to="loc_us-gaap_ImpairmentOfInvestments_01d64efd-4d6f-4770-a225-73153fa6bdb2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_ImpairmentAnalysisCostOfCapitalTheoreticalMarketParticipant_1d32886d-576b-432c-8fe9-cad27b7fa6ed" xlink:href="paa-20211231.xsd#paa_ImpairmentAnalysisCostOfCapitalTheoreticalMarketParticipant"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_1433185f-d3d5-4069-92a7-bb0628409d18" xlink:to="loc_paa_ImpairmentAnalysisCostOfCapitalTheoreticalMarketParticipant_1d32886d-576b-432c-8fe9-cad27b7fa6ed" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncashOrPartNoncashAcquisitionInterestAcquired1_6aa35041-a772-4141-b2d7-9596228e9245" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NoncashOrPartNoncashAcquisitionInterestAcquired1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_1433185f-d3d5-4069-92a7-bb0628409d18" xlink:to="loc_us-gaap_NoncashOrPartNoncashAcquisitionInterestAcquired1_6aa35041-a772-4141-b2d7-9596228e9245" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_UndividedJointInterestOwnershipPercentage_e094b8ab-1062-41de-b091-88a24a302612" xlink:href="paa-20211231.xsd#paa_UndividedJointInterestOwnershipPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_1433185f-d3d5-4069-92a7-bb0628409d18" xlink:to="loc_paa_UndividedJointInterestOwnershipPercentage_e094b8ab-1062-41de-b091-88a24a302612" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_102d6b35-1756-4a19-ab54-5a52bae289e5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_1433185f-d3d5-4069-92a7-bb0628409d18" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_102d6b35-1756-4a19-ab54-5a52bae289e5" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentsFairValueDisclosure_445b3d18-3e69-4f78-8aa3-39a50cf4f8d4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityMethodInvestmentsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_1433185f-d3d5-4069-92a7-bb0628409d18" xlink:to="loc_us-gaap_EquityMethodInvestmentsFairValueDisclosure_445b3d18-3e69-4f78-8aa3-39a50cf4f8d4" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeconsolidationRevaluationOfRetainedInvestmentGainOrLossAmount_a347df39-7955-44d8-932d-e86180dc5c18" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeconsolidationRevaluationOfRetainedInvestmentGainOrLossAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_1433185f-d3d5-4069-92a7-bb0628409d18" xlink:to="loc_us-gaap_DeconsolidationRevaluationOfRetainedInvestmentGainOrLossAmount_a347df39-7955-44d8-932d-e86180dc5c18" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_EquityMethodInvestmentOwnershipPercentageSold_b63e5a86-c696-48b3-85e6-271a61b9f8fd" xlink:href="paa-20211231.xsd#paa_EquityMethodInvestmentOwnershipPercentageSold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_1433185f-d3d5-4069-92a7-bb0628409d18" xlink:to="loc_paa_EquityMethodInvestmentOwnershipPercentageSold_b63e5a86-c696-48b3-85e6-271a61b9f8fd" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromSaleOfEquityMethodInvestments_1f4b7ac6-523a-4e2a-97b8-b7c1fe181113" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromSaleOfEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_1433185f-d3d5-4069-92a7-bb0628409d18" xlink:to="loc_us-gaap_ProceedsFromSaleOfEquityMethodInvestments_1f4b7ac6-523a-4e2a-97b8-b7c1fe181113" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentRealizedGainLossOnDisposal_e9188eee-ec05-4ca6-b612-e8c005eae712" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityMethodInvestmentRealizedGainLossOnDisposal"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_1433185f-d3d5-4069-92a7-bb0628409d18" xlink:to="loc_us-gaap_EquityMethodInvestmentRealizedGainLossOnDisposal_e9188eee-ec05-4ca6-b612-e8c005eae712" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_CapitalContributionsToEquityMethodInvesteesExcludingCapitalizedInterest_bfd51d86-7239-4d9a-b238-7a78401eb9aa" xlink:href="paa-20211231.xsd#paa_CapitalContributionsToEquityMethodInvesteesExcludingCapitalizedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_1433185f-d3d5-4069-92a7-bb0628409d18" xlink:to="loc_paa_CapitalContributionsToEquityMethodInvesteesExcludingCapitalizedInterest_bfd51d86-7239-4d9a-b238-7a78401eb9aa" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestCostsCapitalized_1848e536-cd61-406b-99c4-9180cfb9e78a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestCostsCapitalized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_1433185f-d3d5-4069-92a7-bb0628409d18" xlink:to="loc_us-gaap_InterestCostsCapitalized_1848e536-cd61-406b-99c4-9180cfb9e78a" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentDifferenceBetweenCarryingAmountAndUnderlyingEquity_729c02dc-8f5c-48bb-8037-1916bd500590" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityMethodInvestmentDifferenceBetweenCarryingAmountAndUnderlyingEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_1433185f-d3d5-4069-92a7-bb0628409d18" xlink:to="loc_us-gaap_EquityMethodInvestmentDifferenceBetweenCarryingAmountAndUnderlyingEquity_729c02dc-8f5c-48bb-8037-1916bd500590" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_24013233-4e61-4e7b-a0da-6c723d999f83" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_1433185f-d3d5-4069-92a7-bb0628409d18" xlink:to="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_24013233-4e61-4e7b-a0da-6c723d999f83" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_5b9dbb9a-2c91-4f8b-b69c-2185efe1812d" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_24013233-4e61-4e7b-a0da-6c723d999f83" xlink:to="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_5b9dbb9a-2c91-4f8b-b69c-2185efe1812d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_5b9dbb9a-2c91-4f8b-b69c-2185efe1812d_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_5b9dbb9a-2c91-4f8b-b69c-2185efe1812d" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_5b9dbb9a-2c91-4f8b-b69c-2185efe1812d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_c0d18afc-f615-4103-a98d-eba080a64f35" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_5b9dbb9a-2c91-4f8b-b69c-2185efe1812d" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_c0d18afc-f615-4103-a98d-eba080a64f35" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_BridgeTexPipelineCompanyLLCMember_3228f474-068e-4535-870c-0140e6fb5f37" xlink:href="paa-20211231.xsd#paa_BridgeTexPipelineCompanyLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_c0d18afc-f615-4103-a98d-eba080a64f35" xlink:to="loc_paa_BridgeTexPipelineCompanyLLCMember_3228f474-068e-4535-870c-0140e6fb5f37" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_CactusIIPipelineLLCMember_33c1fbab-aa59-4612-8665-bc9e838554be" xlink:href="paa-20211231.xsd#paa_CactusIIPipelineLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_c0d18afc-f615-4103-a98d-eba080a64f35" xlink:to="loc_paa_CactusIIPipelineLLCMember_33c1fbab-aa59-4612-8665-bc9e838554be" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_CaplinePipelineCompanyLLCMember_8403db18-dd68-40be-b781-35a690721449" xlink:href="paa-20211231.xsd#paa_CaplinePipelineCompanyLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_c0d18afc-f615-4103-a98d-eba080a64f35" xlink:to="loc_paa_CaplinePipelineCompanyLLCMember_8403db18-dd68-40be-b781-35a690721449" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_DiamondPipelineLLCMember_d827c6a2-6165-433d-8f5b-37d7619947e9" xlink:href="paa-20211231.xsd#paa_DiamondPipelineLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_c0d18afc-f615-4103-a98d-eba080a64f35" xlink:to="loc_paa_DiamondPipelineLLCMember_d827c6a2-6165-433d-8f5b-37d7619947e9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_EagleFordPipelineLLCMember_fc583f79-d92c-45c1-bd99-7188d8ad044f" xlink:href="paa-20211231.xsd#paa_EagleFordPipelineLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_c0d18afc-f615-4103-a98d-eba080a64f35" xlink:to="loc_paa_EagleFordPipelineLLCMember_fc583f79-d92c-45c1-bd99-7188d8ad044f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_EagleFordTerminalsCorpusChristiLLCMember_bfda7eaf-6203-45b3-8e8a-fc94349acd04" xlink:href="paa-20211231.xsd#paa_EagleFordTerminalsCorpusChristiLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_c0d18afc-f615-4103-a98d-eba080a64f35" xlink:to="loc_paa_EagleFordTerminalsCorpusChristiLLCMember_bfda7eaf-6203-45b3-8e8a-fc94349acd04" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_OMOGJVLLCMember_8eb4e46c-fdcc-4e2f-8e33-1d2d68a86c30" xlink:href="paa-20211231.xsd#paa_OMOGJVLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_c0d18afc-f615-4103-a98d-eba080a64f35" xlink:to="loc_paa_OMOGJVLLCMember_8eb4e46c-fdcc-4e2f-8e33-1d2d68a86c30" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SaddlehornPipelineCompanyLLCMember_34bf14e5-35a2-4075-a15e-2acba7a7f05b" xlink:href="paa-20211231.xsd#paa_SaddlehornPipelineCompanyLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_c0d18afc-f615-4103-a98d-eba080a64f35" xlink:to="loc_paa_SaddlehornPipelineCompanyLLCMember_34bf14e5-35a2-4075-a15e-2acba7a7f05b" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_WhiteCliffsPipelineLLCMember_b8460b54-f8d5-4089-881f-8e87e47600ad" xlink:href="paa-20211231.xsd#paa_WhiteCliffsPipelineLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_c0d18afc-f615-4103-a98d-eba080a64f35" xlink:to="loc_paa_WhiteCliffsPipelineLLCMember_b8460b54-f8d5-4089-881f-8e87e47600ad" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_WinktoWebsterPipelineLLCMember_75bc8b2d-faf3-49f9-92f9-1241768a6547" xlink:href="paa-20211231.xsd#paa_WinktoWebsterPipelineLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_c0d18afc-f615-4103-a98d-eba080a64f35" xlink:to="loc_paa_WinktoWebsterPipelineLLCMember_75bc8b2d-faf3-49f9-92f9-1241768a6547" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_OtherEquityMethodInvestmentMember_afe89bf9-be15-4676-b4e5-bba1f190c58b" xlink:href="paa-20211231.xsd#paa_OtherEquityMethodInvestmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_c0d18afc-f615-4103-a98d-eba080a64f35" xlink:to="loc_paa_OtherEquityMethodInvestmentMember_afe89bf9-be15-4676-b4e5-bba1f190c58b" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_STACKPipelineLLCMember_78a66c8b-b596-4e2b-9509-8ceffa9a8921" xlink:href="paa-20211231.xsd#paa_STACKPipelineLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_c0d18afc-f615-4103-a98d-eba080a64f35" xlink:to="loc_paa_STACKPipelineLLCMember_78a66c8b-b596-4e2b-9509-8ceffa9a8921" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_RedOakPiplelineLLCMember_dbd96db6-f11e-4853-9727-543ee0cd2d7a" xlink:href="paa-20211231.xsd#paa_RedOakPiplelineLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_c0d18afc-f615-4103-a98d-eba080a64f35" xlink:to="loc_paa_RedOakPiplelineLLCMember_dbd96db6-f11e-4853-9727-543ee0cd2d7a" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_f74f57f0-cc15-4a81-80a6-4a6ad2bf09b2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_24013233-4e61-4e7b-a0da-6c723d999f83" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_f74f57f0-cc15-4a81-80a6-4a6ad2bf09b2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_f74f57f0-cc15-4a81-80a6-4a6ad2bf09b2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_f74f57f0-cc15-4a81-80a6-4a6ad2bf09b2" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_f74f57f0-cc15-4a81-80a6-4a6ad2bf09b2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_a9f335e1-18a7-423f-814f-77cabb10fe92" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_f74f57f0-cc15-4a81-80a6-4a6ad2bf09b2" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_a9f335e1-18a7-423f-814f-77cabb10fe92" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_968bdc8e-7b65-4bdf-95f0-b1b95cab199e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_a9f335e1-18a7-423f-814f-77cabb10fe92" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_968bdc8e-7b65-4bdf-95f0-b1b95cab199e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeAxis_35216179-104d-48a6-baf3-298798cd36ff" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MeasurementInputTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_24013233-4e61-4e7b-a0da-6c723d999f83" xlink:to="loc_us-gaap_MeasurementInputTypeAxis_35216179-104d-48a6-baf3-298798cd36ff" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_35216179-104d-48a6-baf3-298798cd36ff_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_35216179-104d-48a6-baf3-298798cd36ff" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_35216179-104d-48a6-baf3-298798cd36ff_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_de8eb741-c30d-4078-bb0a-2e47114aa7a4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_35216179-104d-48a6-baf3-298798cd36ff" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_de8eb741-c30d-4078-bb0a-2e47114aa7a4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputDiscountRateMember_3177bc5d-2e63-4b51-85d3-6eaec8666ea9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MeasurementInputDiscountRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_de8eb741-c30d-4078-bb0a-2e47114aa7a4" xlink:to="loc_us-gaap_MeasurementInputDiscountRateMember_3177bc5d-2e63-4b51-85d3-6eaec8666ea9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationTechniqueAxis_4549b80f-9c7c-494a-abca-a1463833aa13" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ValuationTechniqueAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_24013233-4e61-4e7b-a0da-6c723d999f83" xlink:to="loc_us-gaap_ValuationTechniqueAxis_4549b80f-9c7c-494a-abca-a1463833aa13" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationTechniqueDomain_4549b80f-9c7c-494a-abca-a1463833aa13_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ValuationTechniqueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ValuationTechniqueAxis_4549b80f-9c7c-494a-abca-a1463833aa13" xlink:to="loc_us-gaap_ValuationTechniqueDomain_4549b80f-9c7c-494a-abca-a1463833aa13_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationTechniqueDomain_ff778ce3-df1c-4006-90ae-a47c4e64fe58" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ValuationTechniqueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ValuationTechniqueAxis_4549b80f-9c7c-494a-abca-a1463833aa13" xlink:to="loc_us-gaap_ValuationTechniqueDomain_ff778ce3-df1c-4006-90ae-a47c4e64fe58" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationTechniqueDiscountedCashFlowMember_a070c3da-0d91-4aff-bc34-ffa7d63f0c98" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ValuationTechniqueDiscountedCashFlowMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationTechniqueDomain_ff778ce3-df1c-4006-90ae-a47c4e64fe58" xlink:to="loc_us-gaap_ValuationTechniqueDiscountedCashFlowMember_a070c3da-0d91-4aff-bc34-ffa7d63f0c98" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipAxis_85ec8e62-fd6e-4232-9c98-5e45f636a7ad" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_OwnershipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_24013233-4e61-4e7b-a0da-6c723d999f83" xlink:to="loc_srt_OwnershipAxis_85ec8e62-fd6e-4232-9c98-5e45f636a7ad" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_85ec8e62-fd6e-4232-9c98-5e45f636a7ad_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_OwnershipAxis_85ec8e62-fd6e-4232-9c98-5e45f636a7ad" xlink:to="loc_srt_OwnershipDomain_85ec8e62-fd6e-4232-9c98-5e45f636a7ad_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_46f3284a-12d9-4f75-80d1-3182da2b3071" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_OwnershipAxis_85ec8e62-fd6e-4232-9c98-5e45f636a7ad" xlink:to="loc_srt_OwnershipDomain_46f3284a-12d9-4f75-80d1-3182da2b3071" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_UndividedJointInterestInCaplinePipelineSystemMember_744e333b-01ae-495a-a8c1-a0e1dd96175f" xlink:href="paa-20211231.xsd#paa_UndividedJointInterestInCaplinePipelineSystemMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_OwnershipDomain_46f3284a-12d9-4f75-80d1-3182da2b3071" xlink:to="loc_paa_UndividedJointInterestInCaplinePipelineSystemMember_744e333b-01ae-495a-a8c1-a0e1dd96175f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_043eea2c-3efd-42ed-a081-d125339fa227" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_24013233-4e61-4e7b-a0da-6c723d999f83" xlink:to="loc_dei_LegalEntityAxis_043eea2c-3efd-42ed-a081-d125339fa227" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_043eea2c-3efd-42ed-a081-d125339fa227_default" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_043eea2c-3efd-42ed-a081-d125339fa227" xlink:to="loc_dei_EntityDomain_043eea2c-3efd-42ed-a081-d125339fa227_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_b4809c6c-c86a-44a8-905b-4f7343a24150" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_043eea2c-3efd-42ed-a081-d125339fa227" xlink:to="loc_dei_EntityDomain_b4809c6c-c86a-44a8-905b-4f7343a24150" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_CaplinePipelineCompanyLLCMember_30c92cc8-06a5-47fd-9e90-1fd9c3b17fd2" xlink:href="paa-20211231.xsd#paa_CaplinePipelineCompanyLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_b4809c6c-c86a-44a8-905b-4f7343a24150" xlink:to="loc_paa_CaplinePipelineCompanyLLCMember_30c92cc8-06a5-47fd-9e90-1fd9c3b17fd2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_d5c7ecbe-4337-42b8-88b0-63615376f5f5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_24013233-4e61-4e7b-a0da-6c723d999f83" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_d5c7ecbe-4337-42b8-88b0-63615376f5f5" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_d5c7ecbe-4337-42b8-88b0-63615376f5f5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_d5c7ecbe-4337-42b8-88b0-63615376f5f5" xlink:to="loc_us-gaap_RelatedPartyDomain_d5c7ecbe-4337-42b8-88b0-63615376f5f5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_4640de64-fb9d-4187-bc89-2597162cafa1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_d5c7ecbe-4337-42b8-88b0-63615376f5f5" xlink:to="loc_us-gaap_RelatedPartyDomain_4640de64-fb9d-4187-bc89-2597162cafa1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvesteeMember_94a19429-64f7-4c2d-bbfe-0e7f53ef0e45" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityMethodInvesteeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_4640de64-fb9d-4187-bc89-2597162cafa1" xlink:to="loc_us-gaap_EquityMethodInvesteeMember_94a19429-64f7-4c2d-bbfe-0e7f53ef0e45" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_b07e4f81-c2a9-456c-a0de-0888f3abcb62" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_24013233-4e61-4e7b-a0da-6c723d999f83" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_b07e4f81-c2a9-456c-a0de-0888f3abcb62" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_b07e4f81-c2a9-456c-a0de-0888f3abcb62_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_b07e4f81-c2a9-456c-a0de-0888f3abcb62" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_b07e4f81-c2a9-456c-a0de-0888f3abcb62_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_948c5a30-10c8-437b-b847-fb6e545f7c0e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_b07e4f81-c2a9-456c-a0de-0888f3abcb62" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_948c5a30-10c8-437b-b847-fb6e545f7c0e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentMember_9d9d0d37-895b-4ca4-8893-429f289b35b9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_948c5a30-10c8-437b-b847-fb6e545f7c0e" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentMember_9d9d0d37-895b-4ca4-8893-429f289b35b9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_1dc4de5a-6336-45e8-a988-1fac8eba47dc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_24013233-4e61-4e7b-a0da-6c723d999f83" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_1dc4de5a-6336-45e8-a988-1fac8eba47dc" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_1dc4de5a-6336-45e8-a988-1fac8eba47dc_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_1dc4de5a-6336-45e8-a988-1fac8eba47dc" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_1dc4de5a-6336-45e8-a988-1fac8eba47dc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_b39d3df0-ba68-4469-a35e-0db5a0098462" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_1dc4de5a-6336-45e8-a988-1fac8eba47dc" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_b39d3df0-ba68-4469-a35e-0db5a0098462" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_GainOnImpairmentOfInvestmentsInUnconsolidatedEntitiesNetMember_023638da-df1b-47ff-82d2-ee20c6fb90bf" xlink:href="paa-20211231.xsd#paa_GainOnImpairmentOfInvestmentsInUnconsolidatedEntitiesNetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_b39d3df0-ba68-4469-a35e-0db5a0098462" xlink:to="loc_paa_GainOnImpairmentOfInvestmentsInUnconsolidatedEntitiesNetMember_023638da-df1b-47ff-82d2-ee20c6fb90bf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_6d287b76-eae2-4dfc-b654-8aa908b40d96" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_24013233-4e61-4e7b-a0da-6c723d999f83" xlink:to="loc_srt_RangeAxis_6d287b76-eae2-4dfc-b654-8aa908b40d96" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_6d287b76-eae2-4dfc-b654-8aa908b40d96_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_6d287b76-eae2-4dfc-b654-8aa908b40d96" xlink:to="loc_srt_RangeMember_6d287b76-eae2-4dfc-b654-8aa908b40d96_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_8dbcd680-6bd3-4ece-81e6-21f676f9147a" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_6d287b76-eae2-4dfc-b654-8aa908b40d96" xlink:to="loc_srt_RangeMember_8dbcd680-6bd3-4ece-81e6-21f676f9147a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_6229a512-9543-4f5e-8d1d-b0fd8bcfeac5" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_8dbcd680-6bd3-4ece-81e6-21f676f9147a" xlink:to="loc_srt_MaximumMember_6229a512-9543-4f5e-8d1d-b0fd8bcfeac5" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/InvestmentsinUnconsolidatedEntitiesSummarizedFinancialInformationDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#InvestmentsinUnconsolidatedEntitiesSummarizedFinancialInformationDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/InvestmentsinUnconsolidatedEntitiesSummarizedFinancialInformationDetails" xlink:type="extended" id="icb14251535f1480594cf39cdfa199fbd_InvestmentsinUnconsolidatedEntitiesSummarizedFinancialInformationDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_a0f4b5d9-24fe-4f27-bcd1-952acaa90387" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrent_1e759fc9-e677-49c2-83aa-4b89da84b8b7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_a0f4b5d9-24fe-4f27-bcd1-952acaa90387" xlink:to="loc_us-gaap_AssetsCurrent_1e759fc9-e677-49c2-83aa-4b89da84b8b7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsNoncurrent_039910db-8941-4da8-934d-c9debe812ab4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetsNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_a0f4b5d9-24fe-4f27-bcd1-952acaa90387" xlink:to="loc_us-gaap_AssetsNoncurrent_039910db-8941-4da8-934d-c9debe812ab4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrent_96aa5abc-b680-45db-933f-b550e3f8c4cb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_a0f4b5d9-24fe-4f27-bcd1-952acaa90387" xlink:to="loc_us-gaap_LiabilitiesCurrent_96aa5abc-b680-45db-933f-b550e3f8c4cb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesNoncurrent_2fd2baa3-eb97-418f-b8ec-bc1e9247acc2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LiabilitiesNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_a0f4b5d9-24fe-4f27-bcd1-952acaa90387" xlink:to="loc_us-gaap_LiabilitiesNoncurrent_2fd2baa3-eb97-418f-b8ec-bc1e9247acc2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_608f710c-7b15-48e9-91f7-880eeaf45153" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_a0f4b5d9-24fe-4f27-bcd1-952acaa90387" xlink:to="loc_us-gaap_Revenues_608f710c-7b15-48e9-91f7-880eeaf45153" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_46f87acb-8660-42dc-8e17-5faf855206cb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_a0f4b5d9-24fe-4f27-bcd1-952acaa90387" xlink:to="loc_us-gaap_OperatingIncomeLoss_46f87acb-8660-42dc-8e17-5faf855206cb" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GrossProfit_65c89ea9-ff1a-4c19-9b73-a635e0f81f94" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GrossProfit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_a0f4b5d9-24fe-4f27-bcd1-952acaa90387" xlink:to="loc_us-gaap_GrossProfit_65c89ea9-ff1a-4c19-9b73-a635e0f81f94" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_05a2f8db-8c8a-4d6e-a28d-d450ba1f5c5d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_a0f4b5d9-24fe-4f27-bcd1-952acaa90387" xlink:to="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_05a2f8db-8c8a-4d6e-a28d-d450ba1f5c5d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeAxis_b9cc1654-cbb7-4867-a203-8fd70add26fc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_05a2f8db-8c8a-4d6e-a28d-d450ba1f5c5d" xlink:to="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeAxis_b9cc1654-cbb7-4867-a203-8fd70add26fc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeDomain_b9cc1654-cbb7-4867-a203-8fd70add26fc_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeAxis_b9cc1654-cbb7-4867-a203-8fd70add26fc" xlink:to="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeDomain_b9cc1654-cbb7-4867-a203-8fd70add26fc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeDomain_6b6e64e5-2f41-49a9-8660-daec5de92277" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeAxis_b9cc1654-cbb7-4867-a203-8fd70add26fc" xlink:to="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeDomain_6b6e64e5-2f41-49a9-8660-daec5de92277" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvesteesMember_9aa243af-5fe1-4fa5-a6cf-66f1dbc17d4d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvesteesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeDomain_6b6e64e5-2f41-49a9-8660-daec5de92277" xlink:to="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvesteesMember_9aa243af-5fe1-4fa5-a6cf-66f1dbc17d4d" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/IntangibleAssetNetScheduleofIntangibleAssetsDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#IntangibleAssetNetScheduleofIntangibleAssetsDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/IntangibleAssetNetScheduleofIntangibleAssetsDetails" xlink:type="extended" id="i31d2d8d5fb10412080de94857deb7f28_IntangibleAssetNetScheduleofIntangibleAssetsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_7029935a-9568-40cf-9d0b-da3e61f5ec9b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_450a2a39-d816-4b1e-86cf-e740474207af" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_7029935a-9568-40cf-9d0b-da3e61f5ec9b" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_450a2a39-d816-4b1e-86cf-e740474207af" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsGross_7eed05a3-036c-44a5-bdbd-9601a011c4bf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_7029935a-9568-40cf-9d0b-da3e61f5ec9b" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsGross_7eed05a3-036c-44a5-bdbd-9601a011c4bf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_4cb61d11-4417-4611-a659-6ede79f5304a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_7029935a-9568-40cf-9d0b-da3e61f5ec9b" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_4cb61d11-4417-4611-a659-6ede79f5304a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_df012470-ea02-487b-af62-393a33c3f148" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_7029935a-9568-40cf-9d0b-da3e61f5ec9b" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_df012470-ea02-487b-af62-393a33c3f148" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_5919a00f-10f9-4c94-8be2-a4686eaa3cf9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_7029935a-9568-40cf-9d0b-da3e61f5ec9b" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_5919a00f-10f9-4c94-8be2-a4686eaa3cf9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_b69d7dc9-e563-4b17-9d65-362556a0743b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_5919a00f-10f9-4c94-8be2-a4686eaa3cf9" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_b69d7dc9-e563-4b17-9d65-362556a0743b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_b69d7dc9-e563-4b17-9d65-362556a0743b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_b69d7dc9-e563-4b17-9d65-362556a0743b" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_b69d7dc9-e563-4b17-9d65-362556a0743b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_70dee04f-1ffb-4812-8779-246bd93bc03f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_b69d7dc9-e563-4b17-9d65-362556a0743b" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_70dee04f-1ffb-4812-8779-246bd93bc03f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerRelationshipsMember_093431c7-cc43-4ff6-9622-412f8afbac79" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CustomerRelationshipsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_70dee04f-1ffb-4812-8779-246bd93bc03f" xlink:to="loc_us-gaap_CustomerRelationshipsMember_093431c7-cc43-4ff6-9622-412f8afbac79" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherIntangibleAssetsMember_d40aee50-93bf-4056-abc9-54c17a8b8ea3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherIntangibleAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_70dee04f-1ffb-4812-8779-246bd93bc03f" xlink:to="loc_us-gaap_OtherIntangibleAssetsMember_d40aee50-93bf-4056-abc9-54c17a8b8ea3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_4365f9d5-8b4b-4063-9416-df892abf680b" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_5919a00f-10f9-4c94-8be2-a4686eaa3cf9" xlink:to="loc_srt_RangeAxis_4365f9d5-8b4b-4063-9416-df892abf680b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_4365f9d5-8b4b-4063-9416-df892abf680b_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_4365f9d5-8b4b-4063-9416-df892abf680b" xlink:to="loc_srt_RangeMember_4365f9d5-8b4b-4063-9416-df892abf680b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_c938c0b7-e9bb-499c-b4e1-bcaaaa8287e6" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_4365f9d5-8b4b-4063-9416-df892abf680b" xlink:to="loc_srt_RangeMember_c938c0b7-e9bb-499c-b4e1-bcaaaa8287e6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_1e1dfa73-1e0f-4d9d-8e1e-7d5797e407df" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_c938c0b7-e9bb-499c-b4e1-bcaaaa8287e6" xlink:to="loc_srt_MinimumMember_1e1dfa73-1e0f-4d9d-8e1e-7d5797e407df" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_614b8344-6f89-4b76-8a04-7344bffb6c40" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_c938c0b7-e9bb-499c-b4e1-bcaaaa8287e6" xlink:to="loc_srt_MaximumMember_614b8344-6f89-4b76-8a04-7344bffb6c40" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/DebtScheduleofDebtDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#DebtScheduleofDebtDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/DebtScheduleofDebtDetails" xlink:type="extended" id="i19f647af4ece4cc1922ee045a49072b3_DebtScheduleofDebtDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_7e3bcc7f-cfb5-4720-ae01-5517062ec35d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermBorrowingsAbstract_6202648e-69e0-4b15-b007-e8f1410c3415" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermBorrowingsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_7e3bcc7f-cfb5-4720-ae01-5517062ec35d" xlink:to="loc_us-gaap_ShortTermBorrowingsAbstract_6202648e-69e0-4b15-b007-e8f1410c3415" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermBorrowings_1c5cfb26-1b3e-4007-8a6c-53703f4ac1a4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermBorrowings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermBorrowingsAbstract_6202648e-69e0-4b15-b007-e8f1410c3415" xlink:to="loc_us-gaap_ShortTermBorrowings_1c5cfb26-1b3e-4007-8a6c-53703f4ac1a4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtCurrent_fe727160-6163-4ac5-a821-bcfb1e39c372" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermBorrowingsAbstract_6202648e-69e0-4b15-b007-e8f1410c3415" xlink:to="loc_us-gaap_DebtCurrent_fe727160-6163-4ac5-a821-bcfb1e39c372" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtWeightedAverageInterestRate_1f70e1c6-1ec9-416d-8067-942ffc237955" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermDebtWeightedAverageInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermBorrowingsAbstract_6202648e-69e0-4b15-b007-e8f1410c3415" xlink:to="loc_us-gaap_ShortTermDebtWeightedAverageInterestRate_1f70e1c6-1ec9-416d-8067-942ffc237955" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_b92e127a-67aa-4151-8776-883ca6e4a8b9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermBorrowingsAbstract_6202648e-69e0-4b15-b007-e8f1410c3415" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_b92e127a-67aa-4151-8776-883ca6e4a8b9" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtAbstract_50ab948e-b9c8-4292-b863-c066caa93776" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_7e3bcc7f-cfb5-4720-ae01-5517062ec35d" xlink:to="loc_us-gaap_LongTermDebtAbstract_50ab948e-b9c8-4292-b863-c066caa93776" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_014a0fd3-56d7-4ded-a0d3-964fd279122e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtAbstract_50ab948e-b9c8-4292-b863-c066caa93776" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_014a0fd3-56d7-4ded-a0d3-964fd279122e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet_cbbb4647-2390-4591-8592-423867f51df5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtAbstract_50ab948e-b9c8-4292-b863-c066caa93776" xlink:to="loc_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet_cbbb4647-2390-4591-8592-423867f51df5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorLongTermNotes_0dd71928-3726-4fd3-a78e-a6d9ff51c864" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SeniorLongTermNotes"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtAbstract_50ab948e-b9c8-4292-b863-c066caa93776" xlink:to="loc_us-gaap_SeniorLongTermNotes_0dd71928-3726-4fd3-a78e-a6d9ff51c864" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLongTermDebtNoncurrent_4edcf87d-14f4-4941-8238-d2f39a9fc5ae" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherLongTermDebtNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtAbstract_50ab948e-b9c8-4292-b863-c066caa93776" xlink:to="loc_us-gaap_OtherLongTermDebtNoncurrent_4edcf87d-14f4-4941-8238-d2f39a9fc5ae" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtAndCapitalLeaseObligations_97781a6f-89a1-4425-b6ea-adc1df14d2ae" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtAndCapitalLeaseObligations"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtAbstract_50ab948e-b9c8-4292-b863-c066caa93776" xlink:to="loc_us-gaap_LongTermDebtAndCapitalLeaseObligations_97781a6f-89a1-4425-b6ea-adc1df14d2ae" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtAndCapitalLeaseObligations_feb06739-b04f-4b30-9adb-176b68329b73" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtAndCapitalLeaseObligations"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtAbstract_50ab948e-b9c8-4292-b863-c066caa93776" xlink:to="loc_us-gaap_DebtAndCapitalLeaseObligations_feb06739-b04f-4b30-9adb-176b68329b73" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFinanceCostsNet_4e8eb39a-ae3f-4950-a4fa-79cc268ae660" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredFinanceCostsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtAbstract_50ab948e-b9c8-4292-b863-c066caa93776" xlink:to="loc_us-gaap_DeferredFinanceCostsNet_4e8eb39a-ae3f-4950-a4fa-79cc268ae660" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtWeightedAverageInterestRate_30639aa5-9a51-4084-861f-e88577ed3ea7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtWeightedAverageInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtAbstract_50ab948e-b9c8-4292-b863-c066caa93776" xlink:to="loc_us-gaap_LongtermDebtWeightedAverageInterestRate_30639aa5-9a51-4084-861f-e88577ed3ea7" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRepurchasedFaceAmount_fda6c5cc-aeab-423a-9044-f709a3272f79" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentRepurchasedFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_7e3bcc7f-cfb5-4720-ae01-5517062ec35d" xlink:to="loc_us-gaap_DebtInstrumentRepurchasedFaceAmount_fda6c5cc-aeab-423a-9044-f709a3272f79" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_73219b91-9901-4b99-bdff-65126a0dc547" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_7e3bcc7f-cfb5-4720-ae01-5517062ec35d" xlink:to="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_73219b91-9901-4b99-bdff-65126a0dc547" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_eba859ae-ab7e-4b85-b94e-a7ba3ccf93da" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_7e3bcc7f-cfb5-4720-ae01-5517062ec35d" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_eba859ae-ab7e-4b85-b94e-a7ba3ccf93da" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFairValue_70412d4d-e078-4ad9-83b3-2863d9eb8fe3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_7e3bcc7f-cfb5-4720-ae01-5517062ec35d" xlink:to="loc_us-gaap_DebtInstrumentFairValue_70412d4d-e078-4ad9-83b3-2863d9eb8fe3" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_4a71cc49-97b2-426c-8d37-b31c03c47223" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_7e3bcc7f-cfb5-4720-ae01-5517062ec35d" xlink:to="loc_us-gaap_DebtInstrumentTable_4a71cc49-97b2-426c-8d37-b31c03c47223" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeAxis_c548a2af-d2f6-42d2-9ac1-e310486a84e9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_4a71cc49-97b2-426c-8d37-b31c03c47223" xlink:to="loc_us-gaap_ShortTermDebtTypeAxis_c548a2af-d2f6-42d2-9ac1-e310486a84e9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_c548a2af-d2f6-42d2-9ac1-e310486a84e9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_c548a2af-d2f6-42d2-9ac1-e310486a84e9" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_c548a2af-d2f6-42d2-9ac1-e310486a84e9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_cfe9ccbb-2d96-45c5-9113-6fc89c982b9b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_c548a2af-d2f6-42d2-9ac1-e310486a84e9" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_cfe9ccbb-2d96-45c5-9113-6fc89c982b9b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_c8ce9f0a-a8b7-404e-8205-7b5c9f7c9d5c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtTypeDomain_cfe9ccbb-2d96-45c5-9113-6fc89c982b9b" xlink:to="loc_us-gaap_LineOfCreditMember_c8ce9f0a-a8b7-404e-8205-7b5c9f7c9d5c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotesMember_874556c3-e339-41d3-b642-71f5a6a8689e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SeniorNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtTypeDomain_cfe9ccbb-2d96-45c5-9113-6fc89c982b9b" xlink:to="loc_us-gaap_SeniorNotesMember_874556c3-e339-41d3-b642-71f5a6a8689e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_OtherDebtMember_a1144fc9-fca5-467a-9eb7-52cf4444c09a" xlink:href="paa-20211231.xsd#paa_OtherDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtTypeDomain_cfe9ccbb-2d96-45c5-9113-6fc89c982b9b" xlink:to="loc_paa_OtherDebtMember_a1144fc9-fca5-467a-9eb7-52cf4444c09a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_e013c57c-ee64-4efb-94d2-0f2c02c578ad" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_4a71cc49-97b2-426c-8d37-b31c03c47223" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_e013c57c-ee64-4efb-94d2-0f2c02c578ad" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_e013c57c-ee64-4efb-94d2-0f2c02c578ad_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_e013c57c-ee64-4efb-94d2-0f2c02c578ad" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_e013c57c-ee64-4efb-94d2-0f2c02c578ad_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_d2a489ce-71a0-4b9b-8323-c1de4863d322" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_e013c57c-ee64-4efb-94d2-0f2c02c578ad" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_d2a489ce-71a0-4b9b-8323-c1de4863d322" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotesMember_42a77ce9-f293-41cc-bbdd-607a576c31b4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SeniorNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_d2a489ce-71a0-4b9b-8323-c1de4863d322" xlink:to="loc_us-gaap_SeniorNotesMember_42a77ce9-f293-41cc-bbdd-607a576c31b4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_TermLoanMember_2e4142ec-96d9-4335-b310-be52855b3f79" xlink:href="paa-20211231.xsd#paa_TermLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_d2a489ce-71a0-4b9b-8323-c1de4863d322" xlink:to="loc_paa_TermLoanMember_2e4142ec-96d9-4335-b310-be52855b3f79" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_OtherLongTermDebtMember_56dd2783-ace3-4eb5-9291-9c91344ca811" xlink:href="paa-20211231.xsd#paa_OtherLongTermDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_d2a489ce-71a0-4b9b-8323-c1de4863d322" xlink:to="loc_paa_OtherLongTermDebtMember_56dd2783-ace3-4eb5-9291-9c91344ca811" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_240513c5-5b94-447f-8bd4-6205476726b0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_4a71cc49-97b2-426c-8d37-b31c03c47223" xlink:to="loc_us-gaap_DebtInstrumentAxis_240513c5-5b94-447f-8bd4-6205476726b0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_240513c5-5b94-447f-8bd4-6205476726b0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_240513c5-5b94-447f-8bd4-6205476726b0" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_240513c5-5b94-447f-8bd4-6205476726b0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_7877d5d3-9ff4-4eab-8a38-8afa351805cf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_240513c5-5b94-447f-8bd4-6205476726b0" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_7877d5d3-9ff4-4eab-8a38-8afa351805cf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPaperMember_c4ccb84d-2163-49da-ab6b-435ba7b984b7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommercialPaperMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_7877d5d3-9ff4-4eab-8a38-8afa351805cf" xlink:to="loc_us-gaap_CommercialPaperMember_c4ccb84d-2163-49da-ab6b-435ba7b984b7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SeniorSecuredHedgedInventoryFacilityMember_677c2623-3d49-4f7a-b78e-a1f8c7cf43f1" xlink:href="paa-20211231.xsd#paa_SeniorSecuredHedgedInventoryFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_7877d5d3-9ff4-4eab-8a38-8afa351805cf" xlink:to="loc_paa_SeniorSecuredHedgedInventoryFacilityMember_677c2623-3d49-4f7a-b78e-a1f8c7cf43f1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SeniorNotesDueInJune2022At365PercentMember_cd298898-9b16-4950-aeed-31d0186614b9" xlink:href="paa-20211231.xsd#paa_SeniorNotesDueInJune2022At365PercentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_7877d5d3-9ff4-4eab-8a38-8afa351805cf" xlink:to="loc_paa_SeniorNotesDueInJune2022At365PercentMember_cd298898-9b16-4950-aeed-31d0186614b9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SeniorNotesDueInJanuary2023At285PercentMember_5017037b-5b10-48fc-97ab-8692e0aa78e3" xlink:href="paa-20211231.xsd#paa_SeniorNotesDueInJanuary2023At285PercentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_7877d5d3-9ff4-4eab-8a38-8afa351805cf" xlink:to="loc_paa_SeniorNotesDueInJanuary2023At285PercentMember_5017037b-5b10-48fc-97ab-8692e0aa78e3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SeniorNotesDueInOctober2023At385PercentMember_3b6ca324-abb4-4c8e-b653-96b2968b59c7" xlink:href="paa-20211231.xsd#paa_SeniorNotesDueInOctober2023At385PercentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_7877d5d3-9ff4-4eab-8a38-8afa351805cf" xlink:to="loc_paa_SeniorNotesDueInOctober2023At385PercentMember_3b6ca324-abb4-4c8e-b653-96b2968b59c7" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SeniorNotesDueInNovember2024At360PercentMember_a1eb794a-9bba-40aa-a3ea-633ea6a3ca77" xlink:href="paa-20211231.xsd#paa_SeniorNotesDueInNovember2024At360PercentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_7877d5d3-9ff4-4eab-8a38-8afa351805cf" xlink:to="loc_paa_SeniorNotesDueInNovember2024At360PercentMember_a1eb794a-9bba-40aa-a3ea-633ea6a3ca77" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SeniorNotesDueInOctober2025At465PercentMember_2a9b90aa-23a3-4035-950a-6b4e921a064d" xlink:href="paa-20211231.xsd#paa_SeniorNotesDueInOctober2025At465PercentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_7877d5d3-9ff4-4eab-8a38-8afa351805cf" xlink:to="loc_paa_SeniorNotesDueInOctober2025At465PercentMember_2a9b90aa-23a3-4035-950a-6b4e921a064d" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SeniorNotesDueinDecember2026At4.50PercentMember_e8816afb-b1a4-4034-b972-a93a179749b5" xlink:href="paa-20211231.xsd#paa_SeniorNotesDueinDecember2026At4.50PercentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_7877d5d3-9ff4-4eab-8a38-8afa351805cf" xlink:to="loc_paa_SeniorNotesDueinDecember2026At4.50PercentMember_e8816afb-b1a4-4034-b972-a93a179749b5" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SeniorNotesDueInDecember2029At355PercentMember_9d862290-a5c7-444f-8b21-d813aad0f22d" xlink:href="paa-20211231.xsd#paa_SeniorNotesDueInDecember2029At355PercentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_7877d5d3-9ff4-4eab-8a38-8afa351805cf" xlink:to="loc_paa_SeniorNotesDueInDecember2029At355PercentMember_9d862290-a5c7-444f-8b21-d813aad0f22d" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SeniorNotesDueInSeptember2030At380PercentMember_dde59e87-f214-4f88-a83b-76a3beccb0e6" xlink:href="paa-20211231.xsd#paa_SeniorNotesDueInSeptember2030At380PercentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_7877d5d3-9ff4-4eab-8a38-8afa351805cf" xlink:to="loc_paa_SeniorNotesDueInSeptember2030At380PercentMember_dde59e87-f214-4f88-a83b-76a3beccb0e6" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SeniorNotesDueInMay2036At670PercentMember_0d4af7c5-5965-4bc8-86b1-674b1620fe4c" xlink:href="paa-20211231.xsd#paa_SeniorNotesDueInMay2036At670PercentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_7877d5d3-9ff4-4eab-8a38-8afa351805cf" xlink:to="loc_paa_SeniorNotesDueInMay2036At670PercentMember_0d4af7c5-5965-4bc8-86b1-674b1620fe4c" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SeniorNotesDueInJanuary2037At665PercentMember_d5e3937c-3e37-494a-99d8-a76a9f8aa2d8" xlink:href="paa-20211231.xsd#paa_SeniorNotesDueInJanuary2037At665PercentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_7877d5d3-9ff4-4eab-8a38-8afa351805cf" xlink:to="loc_paa_SeniorNotesDueInJanuary2037At665PercentMember_d5e3937c-3e37-494a-99d8-a76a9f8aa2d8" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SeniorNotesDueInJune2042At515PercentMember_9e8a2ce1-1390-4eae-8962-4145d7926934" xlink:href="paa-20211231.xsd#paa_SeniorNotesDueInJune2042At515PercentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_7877d5d3-9ff4-4eab-8a38-8afa351805cf" xlink:to="loc_paa_SeniorNotesDueInJune2042At515PercentMember_9e8a2ce1-1390-4eae-8962-4145d7926934" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SeniorNotesDueInJanuary2043At430PercentMember_5b2283fd-bccd-47f0-9776-cb3f306951cb" xlink:href="paa-20211231.xsd#paa_SeniorNotesDueInJanuary2043At430PercentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_7877d5d3-9ff4-4eab-8a38-8afa351805cf" xlink:to="loc_paa_SeniorNotesDueInJanuary2043At430PercentMember_5b2283fd-bccd-47f0-9776-cb3f306951cb" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SeniorNotesDueInJune2044At470PercentMember_47ae69f1-9e0f-4f1f-b2c9-b68d5979707c" xlink:href="paa-20211231.xsd#paa_SeniorNotesDueInJune2044At470PercentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_7877d5d3-9ff4-4eab-8a38-8afa351805cf" xlink:to="loc_paa_SeniorNotesDueInJune2044At470PercentMember_47ae69f1-9e0f-4f1f-b2c9-b68d5979707c" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SeniorNotesDueInFebruary2045At490PercentMember_9e0b6778-7592-4000-9d1f-ab8b2d34cc6a" xlink:href="paa-20211231.xsd#paa_SeniorNotesDueInFebruary2045At490PercentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_7877d5d3-9ff4-4eab-8a38-8afa351805cf" xlink:to="loc_paa_SeniorNotesDueInFebruary2045At490PercentMember_9e0b6778-7592-4000-9d1f-ab8b2d34cc6a" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_GOZoneTermLoansMember_855ec967-9dd0-467d-9a62-1eb9ea7a8de3" xlink:href="paa-20211231.xsd#paa_GOZoneTermLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_7877d5d3-9ff4-4eab-8a38-8afa351805cf" xlink:to="loc_paa_GOZoneTermLoansMember_855ec967-9dd0-467d-9a62-1eb9ea7a8de3" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_285861fd-d267-49c4-8928-9f90c647b399" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_4a71cc49-97b2-426c-8d37-b31c03c47223" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_285861fd-d267-49c4-8928-9f90c647b399" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_285861fd-d267-49c4-8928-9f90c647b399_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_285861fd-d267-49c4-8928-9f90c647b399" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_285861fd-d267-49c4-8928-9f90c647b399_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_6aecf9db-c7a6-4d33-90dd-4ef5bf01ffbe" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_285861fd-d267-49c4-8928-9f90c647b399" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_6aecf9db-c7a6-4d33-90dd-4ef5bf01ffbe" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_b78fae27-935b-45f0-b029-01eb013338e3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_6aecf9db-c7a6-4d33-90dd-4ef5bf01ffbe" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_b78fae27-935b-45f0-b029-01eb013338e3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_9db4e54e-7c2f-4099-9881-9ff14a806958" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_4a71cc49-97b2-426c-8d37-b31c03c47223" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_9db4e54e-7c2f-4099-9881-9ff14a806958" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_9db4e54e-7c2f-4099-9881-9ff14a806958_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_9db4e54e-7c2f-4099-9881-9ff14a806958" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_9db4e54e-7c2f-4099-9881-9ff14a806958_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_718d453c-9e9f-4dea-bd46-1be92f748d0a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_9db4e54e-7c2f-4099-9881-9ff14a806958" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_718d453c-9e9f-4dea-bd46-1be92f748d0a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpenseMember_24b23129-01a3-4673-ab7b-a47a30fd1d37" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherNonoperatingIncomeExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_718d453c-9e9f-4dea-bd46-1be92f748d0a" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpenseMember_24b23129-01a3-4673-ab7b-a47a30fd1d37" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/DebtCommercialPaperandCreditFacilitiesDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#DebtCommercialPaperandCreditFacilitiesDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/DebtCommercialPaperandCreditFacilitiesDetails" xlink:type="extended" id="i82b993584b594e1d8c1b520fc45bff22_DebtCommercialPaperandCreditFacilitiesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_e59a9e31-495f-468a-a720-10709edd31fb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_ef5cfe58-fedd-479b-92ee-c4beb2f063a3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_e59a9e31-495f-468a-a720-10709edd31fb" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_ef5cfe58-fedd-479b-92ee-c4beb2f063a3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_e56ba45a-5a44-4329-8035-2606490950c6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_e59a9e31-495f-468a-a720-10709edd31fb" xlink:to="loc_us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_e56ba45a-5a44-4329-8035-2606490950c6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_NumberOfOneYearExtensionsProvidedForUnderAgreement_3582f28d-311f-4787-a121-4e73a9dc1d5e" xlink:href="paa-20211231.xsd#paa_NumberOfOneYearExtensionsProvidedForUnderAgreement"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_e59a9e31-495f-468a-a720-10709edd31fb" xlink:to="loc_paa_NumberOfOneYearExtensionsProvidedForUnderAgreement_3582f28d-311f-4787-a121-4e73a9dc1d5e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_LineOfCreditFacilityPeriodForWhichTermOfCreditFacilityMayBeExtended_23d2f029-3c3c-46a6-807f-cdd6dc4a392f" xlink:href="paa-20211231.xsd#paa_LineOfCreditFacilityPeriodForWhichTermOfCreditFacilityMayBeExtended"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_e59a9e31-495f-468a-a720-10709edd31fb" xlink:to="loc_paa_LineOfCreditFacilityPeriodForWhichTermOfCreditFacilityMayBeExtended_23d2f029-3c3c-46a6-807f-cdd6dc4a392f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_DebtNumberOfInstruments_15220edc-9398-4ec0-8b3c-13426d10ec82" xlink:href="paa-20211231.xsd#paa_DebtNumberOfInstruments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_e59a9e31-495f-468a-a720-10709edd31fb" xlink:to="loc_paa_DebtNumberOfInstruments_15220edc-9398-4ec0-8b3c-13426d10ec82" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_0a8b16cb-bfe1-4acf-9a81-9f22659382be" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_e59a9e31-495f-468a-a720-10709edd31fb" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_0a8b16cb-bfe1-4acf-9a81-9f22659382be" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_1eb24fec-c136-4f3d-9ab8-d27e23646f59" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_e59a9e31-495f-468a-a720-10709edd31fb" xlink:to="loc_us-gaap_DebtInstrumentTable_1eb24fec-c136-4f3d-9ab8-d27e23646f59" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_c0651cfc-28b5-4a59-aca5-c9f87cbae631" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_1eb24fec-c136-4f3d-9ab8-d27e23646f59" xlink:to="loc_us-gaap_DebtInstrumentAxis_c0651cfc-28b5-4a59-aca5-c9f87cbae631" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_c0651cfc-28b5-4a59-aca5-c9f87cbae631_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_c0651cfc-28b5-4a59-aca5-c9f87cbae631" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_c0651cfc-28b5-4a59-aca5-c9f87cbae631_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_352fdb1c-e250-4f85-b3d9-5e75b5479ed0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_c0651cfc-28b5-4a59-aca5-c9f87cbae631" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_352fdb1c-e250-4f85-b3d9-5e75b5479ed0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SeniorUnsecuredRevolvingCreditFacilityMember_7284b4fa-3fb4-4ac4-9455-71fc33527ded" xlink:href="paa-20211231.xsd#paa_SeniorUnsecuredRevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_352fdb1c-e250-4f85-b3d9-5e75b5479ed0" xlink:to="loc_paa_SeniorUnsecuredRevolvingCreditFacilityMember_7284b4fa-3fb4-4ac4-9455-71fc33527ded" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_GOZoneTermLoansMember_d984268a-956e-422d-8812-13f2884aa2e5" xlink:href="paa-20211231.xsd#paa_GOZoneTermLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_352fdb1c-e250-4f85-b3d9-5e75b5479ed0" xlink:to="loc_paa_GOZoneTermLoansMember_d984268a-956e-422d-8812-13f2884aa2e5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_GOZoneTermLoanSeries2009Member_c5e3d4d0-5204-4e8f-b1a5-f7bdb6ba0685" xlink:href="paa-20211231.xsd#paa_GOZoneTermLoanSeries2009Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_GOZoneTermLoansMember_d984268a-956e-422d-8812-13f2884aa2e5" xlink:to="loc_paa_GOZoneTermLoanSeries2009Member_c5e3d4d0-5204-4e8f-b1a5-f7bdb6ba0685" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_GOZoneTermLoanSeries2010Member_53edb75f-432d-4d54-a74e-0ade680b58de" xlink:href="paa-20211231.xsd#paa_GOZoneTermLoanSeries2010Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_GOZoneTermLoansMember_d984268a-956e-422d-8812-13f2884aa2e5" xlink:to="loc_paa_GOZoneTermLoanSeries2010Member_53edb75f-432d-4d54-a74e-0ade680b58de" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_23123401-e104-40bd-a2b8-88f6f99beb01" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_1eb24fec-c136-4f3d-9ab8-d27e23646f59" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_23123401-e104-40bd-a2b8-88f6f99beb01" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_23123401-e104-40bd-a2b8-88f6f99beb01_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_23123401-e104-40bd-a2b8-88f6f99beb01" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_23123401-e104-40bd-a2b8-88f6f99beb01_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_eb4fb74d-5fc5-4ae9-b4c9-d9f0e89c228c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_23123401-e104-40bd-a2b8-88f6f99beb01" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_eb4fb74d-5fc5-4ae9-b4c9-d9f0e89c228c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_TermLoanMember_8bfa8e59-439a-40de-bd77-f5081e6e0c78" xlink:href="paa-20211231.xsd#paa_TermLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_eb4fb74d-5fc5-4ae9-b4c9-d9f0e89c228c" xlink:to="loc_paa_TermLoanMember_8bfa8e59-439a-40de-bd77-f5081e6e0c78" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_25942f72-0ed9-4b63-ad43-747e7a4da4da" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_1eb24fec-c136-4f3d-9ab8-d27e23646f59" xlink:to="loc_us-gaap_CreditFacilityAxis_25942f72-0ed9-4b63-ad43-747e7a4da4da" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_25942f72-0ed9-4b63-ad43-747e7a4da4da_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_25942f72-0ed9-4b63-ad43-747e7a4da4da" xlink:to="loc_us-gaap_CreditFacilityDomain_25942f72-0ed9-4b63-ad43-747e7a4da4da_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_f81a997e-41dc-493f-99a2-3cf6936abe36" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_25942f72-0ed9-4b63-ad43-747e7a4da4da" xlink:to="loc_us-gaap_CreditFacilityDomain_f81a997e-41dc-493f-99a2-3cf6936abe36" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPaperMember_14a91691-523b-4e33-b207-f0745192e715" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommercialPaperMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_f81a997e-41dc-493f-99a2-3cf6936abe36" xlink:to="loc_us-gaap_CommercialPaperMember_14a91691-523b-4e33-b207-f0745192e715" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SeniorSecuredHedgedInventoryFacilityMember_7f11a959-5950-4876-b98c-fa049f7f66f6" xlink:href="paa-20211231.xsd#paa_SeniorSecuredHedgedInventoryFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_f81a997e-41dc-493f-99a2-3cf6936abe36" xlink:to="loc_paa_SeniorSecuredHedgedInventoryFacilityMember_7f11a959-5950-4876-b98c-fa049f7f66f6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SeniorUnsecuredRevolvingCreditFacilityMember_69ad6052-d8f4-4c13-9a92-f385fa4a2083" xlink:href="paa-20211231.xsd#paa_SeniorUnsecuredRevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_f81a997e-41dc-493f-99a2-3cf6936abe36" xlink:to="loc_paa_SeniorUnsecuredRevolvingCreditFacilityMember_69ad6052-d8f4-4c13-9a92-f385fa4a2083" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeAxis_15c29d9b-c750-41b6-aecd-d30ce9ce9948" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_1eb24fec-c136-4f3d-9ab8-d27e23646f59" xlink:to="loc_us-gaap_ShortTermDebtTypeAxis_15c29d9b-c750-41b6-aecd-d30ce9ce9948" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_15c29d9b-c750-41b6-aecd-d30ce9ce9948_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_15c29d9b-c750-41b6-aecd-d30ce9ce9948" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_15c29d9b-c750-41b6-aecd-d30ce9ce9948_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_6d8ea9b0-ef07-43a2-b63f-ef042d1de939" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_15c29d9b-c750-41b6-aecd-d30ce9ce9948" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_6d8ea9b0-ef07-43a2-b63f-ef042d1de939" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StandbyLettersOfCreditMember_a4cf18cd-2e80-48e6-9c7a-c716cc2f6be9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StandbyLettersOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtTypeDomain_6d8ea9b0-ef07-43a2-b63f-ef042d1de939" xlink:to="loc_us-gaap_StandbyLettersOfCreditMember_a4cf18cd-2e80-48e6-9c7a-c716cc2f6be9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_69cdc69b-fbdb-4ccc-99e1-e938e23ab09a" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_1eb24fec-c136-4f3d-9ab8-d27e23646f59" xlink:to="loc_srt_RangeAxis_69cdc69b-fbdb-4ccc-99e1-e938e23ab09a" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_69cdc69b-fbdb-4ccc-99e1-e938e23ab09a_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_69cdc69b-fbdb-4ccc-99e1-e938e23ab09a" xlink:to="loc_srt_RangeMember_69cdc69b-fbdb-4ccc-99e1-e938e23ab09a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_04ee817c-df49-45ef-b276-202ba5b58828" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_69cdc69b-fbdb-4ccc-99e1-e938e23ab09a" xlink:to="loc_srt_RangeMember_04ee817c-df49-45ef-b276-202ba5b58828" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_c2c7ecac-7e3d-42b9-8446-1819331cf196" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_04ee817c-df49-45ef-b276-202ba5b58828" xlink:to="loc_srt_MinimumMember_c2c7ecac-7e3d-42b9-8446-1819331cf196" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/DebtSeniorNotesDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#DebtSeniorNotesDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/DebtSeniorNotesDetails" xlink:type="extended" id="i81ccef712f7043d3b17074510f70a4e6_DebtSeniorNotesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_bf22ba61-3aa0-405a-9269-8423d5df0d42" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipOwnershipInterest_adff4ce0-ed07-4795-94c4-9f94789434fa" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipOwnershipInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_bf22ba61-3aa0-405a-9269-8423d5df0d42" xlink:to="loc_us-gaap_SubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipOwnershipInterest_adff4ce0-ed07-4795-94c4-9f94789434fa" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_41b64f04-57ac-4884-893f-65b948248df0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_bf22ba61-3aa0-405a-9269-8423d5df0d42" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_41b64f04-57ac-4884-893f-65b948248df0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SeniorNotesPublicOfferingPrice_5cda8cce-189b-4f00-9107-f05a2a44de91" xlink:href="paa-20211231.xsd#paa_SeniorNotesPublicOfferingPrice"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_bf22ba61-3aa0-405a-9269-8423d5df0d42" xlink:to="loc_paa_SeniorNotesPublicOfferingPrice_5cda8cce-189b-4f00-9107-f05a2a44de91" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_b4c93878-8f8c-4261-b223-2e99370b8d5c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_bf22ba61-3aa0-405a-9269-8423d5df0d42" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_b4c93878-8f8c-4261-b223-2e99370b8d5c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfSeniorDebt_af1ce052-f9f5-474f-a7ab-182c1290a6ed" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RepaymentsOfSeniorDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_bf22ba61-3aa0-405a-9269-8423d5df0d42" xlink:to="loc_us-gaap_RepaymentsOfSeniorDebt_af1ce052-f9f5-474f-a7ab-182c1290a6ed" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_7bba9b81-2944-487a-8b7f-8cc0a4c0aadc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_bf22ba61-3aa0-405a-9269-8423d5df0d42" xlink:to="loc_us-gaap_DebtInstrumentTable_7bba9b81-2944-487a-8b7f-8cc0a4c0aadc" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipAxis_85397bb2-c722-4cf7-9081-44cca5652d75" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_OwnershipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_7bba9b81-2944-487a-8b7f-8cc0a4c0aadc" xlink:to="loc_srt_OwnershipAxis_85397bb2-c722-4cf7-9081-44cca5652d75" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_85397bb2-c722-4cf7-9081-44cca5652d75_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_OwnershipAxis_85397bb2-c722-4cf7-9081-44cca5652d75" xlink:to="loc_srt_OwnershipDomain_85397bb2-c722-4cf7-9081-44cca5652d75_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_50eedbba-a1dc-4996-bd78-2d07382345d8" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_OwnershipAxis_85397bb2-c722-4cf7-9081-44cca5652d75" xlink:to="loc_srt_OwnershipDomain_50eedbba-a1dc-4996-bd78-2d07382345d8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_ConsolidatedFinanceSubsidiaryIssuerMember_1b267131-d063-436f-88ae-c5f45320fe14" xlink:href="paa-20211231.xsd#paa_ConsolidatedFinanceSubsidiaryIssuerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_OwnershipDomain_50eedbba-a1dc-4996-bd78-2d07382345d8" xlink:to="loc_paa_ConsolidatedFinanceSubsidiaryIssuerMember_1b267131-d063-436f-88ae-c5f45320fe14" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_86c24547-f83d-4804-b310-455eecf64db4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_7bba9b81-2944-487a-8b7f-8cc0a4c0aadc" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_86c24547-f83d-4804-b310-455eecf64db4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_86c24547-f83d-4804-b310-455eecf64db4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_86c24547-f83d-4804-b310-455eecf64db4" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_86c24547-f83d-4804-b310-455eecf64db4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_e94eceda-78de-4ee2-8722-385e835d905e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_86c24547-f83d-4804-b310-455eecf64db4" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_e94eceda-78de-4ee2-8722-385e835d905e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotesMember_2db1faac-945c-45a7-827a-cc75dd1b68ca" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SeniorNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_e94eceda-78de-4ee2-8722-385e835d905e" xlink:to="loc_us-gaap_SeniorNotesMember_2db1faac-945c-45a7-827a-cc75dd1b68ca" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_759950e4-7eaf-46a4-92cc-8c2f2f0b9e50" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_7bba9b81-2944-487a-8b7f-8cc0a4c0aadc" xlink:to="loc_us-gaap_DebtInstrumentAxis_759950e4-7eaf-46a4-92cc-8c2f2f0b9e50" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_759950e4-7eaf-46a4-92cc-8c2f2f0b9e50_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_759950e4-7eaf-46a4-92cc-8c2f2f0b9e50" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_759950e4-7eaf-46a4-92cc-8c2f2f0b9e50_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_c3ea85d1-6eb4-477b-b3ff-31da001b36ac" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_759950e4-7eaf-46a4-92cc-8c2f2f0b9e50" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_c3ea85d1-6eb4-477b-b3ff-31da001b36ac" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SeniorNotesDueInSeptember2030At380PercentMember_6d7babc7-0051-465c-a4d0-1de3a3b80a5c" xlink:href="paa-20211231.xsd#paa_SeniorNotesDueInSeptember2030At380PercentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_c3ea85d1-6eb4-477b-b3ff-31da001b36ac" xlink:to="loc_paa_SeniorNotesDueInSeptember2030At380PercentMember_6d7babc7-0051-465c-a4d0-1de3a3b80a5c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SeniorNotesDueInDecember2029At355PercentMember_e10c5adf-5563-4e2f-a8cc-f8861cf7ba40" xlink:href="paa-20211231.xsd#paa_SeniorNotesDueInDecember2029At355PercentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_c3ea85d1-6eb4-477b-b3ff-31da001b36ac" xlink:to="loc_paa_SeniorNotesDueInDecember2029At355PercentMember_e10c5adf-5563-4e2f-a8cc-f8861cf7ba40" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SeniorNotesDueInFebruary2021At500PercentMember_57c7b059-b6e9-4936-8b91-43d6abc02bdc" xlink:href="paa-20211231.xsd#paa_SeniorNotesDueInFebruary2021At500PercentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_c3ea85d1-6eb4-477b-b3ff-31da001b36ac" xlink:to="loc_paa_SeniorNotesDueInFebruary2021At500PercentMember_57c7b059-b6e9-4936-8b91-43d6abc02bdc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SeniorNotesDueInDecember2019At260PercentMember_5c62a7e3-332d-4f2c-96ab-91fb291af67b" xlink:href="paa-20211231.xsd#paa_SeniorNotesDueInDecember2019At260PercentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_c3ea85d1-6eb4-477b-b3ff-31da001b36ac" xlink:to="loc_paa_SeniorNotesDueInDecember2019At260PercentMember_5c62a7e3-332d-4f2c-96ab-91fb291af67b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SeniorNotesDueInJanuary2020At575PercentMember_46aa2ed3-704e-423c-b268-76c5c69c717d" xlink:href="paa-20211231.xsd#paa_SeniorNotesDueInJanuary2020At575PercentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_c3ea85d1-6eb4-477b-b3ff-31da001b36ac" xlink:to="loc_paa_SeniorNotesDueInJanuary2020At575PercentMember_46aa2ed3-704e-423c-b268-76c5c69c717d" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/DebtDebtCovenantsDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#DebtDebtCovenantsDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/DebtDebtCovenantsDetails" xlink:type="extended" id="i905517c8e0864851bcf0b6d29cd4c72b_DebtDebtCovenantsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_4a037b2f-f7f9-47e8-a65c-5bb45b62e43c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_DebtInstrumentCoverageRatioDebtToEBITDAMaximum_89cbec5e-2ef6-431d-8bab-1a08701da7a9" xlink:href="paa-20211231.xsd#paa_DebtInstrumentCoverageRatioDebtToEBITDAMaximum"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_4a037b2f-f7f9-47e8-a65c-5bb45b62e43c" xlink:to="loc_paa_DebtInstrumentCoverageRatioDebtToEBITDAMaximum_89cbec5e-2ef6-431d-8bab-1a08701da7a9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_DebtInstrumentCoverageRatioDebtToEBITDAAcquisitionPeriodMaximum_d4324cbe-4488-4865-bfc4-455c962b189b" xlink:href="paa-20211231.xsd#paa_DebtInstrumentCoverageRatioDebtToEBITDAAcquisitionPeriodMaximum"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_4a037b2f-f7f9-47e8-a65c-5bb45b62e43c" xlink:to="loc_paa_DebtInstrumentCoverageRatioDebtToEBITDAAcquisitionPeriodMaximum_d4324cbe-4488-4865-bfc4-455c962b189b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_AcquisitionMeasurementPeriodThreshold_672af235-ccd6-4c7e-9bbe-50de9f95b040" xlink:href="paa-20211231.xsd#paa_AcquisitionMeasurementPeriodThreshold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_4a037b2f-f7f9-47e8-a65c-5bb45b62e43c" xlink:to="loc_paa_AcquisitionMeasurementPeriodThreshold_672af235-ccd6-4c7e-9bbe-50de9f95b040" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfDebt_7717f046-7127-442f-b06e-baffecacbf3e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromIssuanceOfDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_4a037b2f-f7f9-47e8-a65c-5bb45b62e43c" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfDebt_7717f046-7127-442f-b06e-baffecacbf3e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfDebt_e58a836f-d5ad-4da7-a1d4-0457eca34dd2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RepaymentsOfDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_4a037b2f-f7f9-47e8-a65c-5bb45b62e43c" xlink:to="loc_us-gaap_RepaymentsOfDebt_e58a836f-d5ad-4da7-a1d4-0457eca34dd2" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTerm_79368c5b-2cb0-4cb0-8949-8a4a6bb1982d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_4a037b2f-f7f9-47e8-a65c-5bb45b62e43c" xlink:to="loc_us-gaap_DebtInstrumentTerm_79368c5b-2cb0-4cb0-8949-8a4a6bb1982d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LettersOfCreditOutstandingAmount_a2793300-49f9-4312-9878-369fac41cc1b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LettersOfCreditOutstandingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_4a037b2f-f7f9-47e8-a65c-5bb45b62e43c" xlink:to="loc_us-gaap_LettersOfCreditOutstandingAmount_a2793300-49f9-4312-9878-369fac41cc1b" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_0fef6063-dfe2-403c-a28d-5f55f8ebeb8b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_4a037b2f-f7f9-47e8-a65c-5bb45b62e43c" xlink:to="loc_us-gaap_DebtInstrumentTable_0fef6063-dfe2-403c-a28d-5f55f8ebeb8b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeAxis_41009eeb-8e37-410c-81d9-90ead370ddcb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_0fef6063-dfe2-403c-a28d-5f55f8ebeb8b" xlink:to="loc_us-gaap_ShortTermDebtTypeAxis_41009eeb-8e37-410c-81d9-90ead370ddcb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_41009eeb-8e37-410c-81d9-90ead370ddcb_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_41009eeb-8e37-410c-81d9-90ead370ddcb" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_41009eeb-8e37-410c-81d9-90ead370ddcb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_534fe7c3-e59e-4a41-a614-848dc3a27ea4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_41009eeb-8e37-410c-81d9-90ead370ddcb" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_534fe7c3-e59e-4a41-a614-848dc3a27ea4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StandbyLettersOfCreditMember_d0353c86-eede-4b0b-bdbc-66c49e2a15ba" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StandbyLettersOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtTypeDomain_534fe7c3-e59e-4a41-a614-848dc3a27ea4" xlink:to="loc_us-gaap_StandbyLettersOfCreditMember_d0353c86-eede-4b0b-bdbc-66c49e2a15ba" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_12980eae-9d85-44ce-a0ee-dfa9b8db442c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_0fef6063-dfe2-403c-a28d-5f55f8ebeb8b" xlink:to="loc_us-gaap_CreditFacilityAxis_12980eae-9d85-44ce-a0ee-dfa9b8db442c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_12980eae-9d85-44ce-a0ee-dfa9b8db442c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_12980eae-9d85-44ce-a0ee-dfa9b8db442c" xlink:to="loc_us-gaap_CreditFacilityDomain_12980eae-9d85-44ce-a0ee-dfa9b8db442c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_3440d49c-6094-468a-ad44-b3626ec9fad1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_12980eae-9d85-44ce-a0ee-dfa9b8db442c" xlink:to="loc_us-gaap_CreditFacilityDomain_3440d49c-6094-468a-ad44-b3626ec9fad1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_LineOfCreditAndCommercialPaperMember_8912ef6c-5ee6-40cf-ac10-3ea9c463654a" xlink:href="paa-20211231.xsd#paa_LineOfCreditAndCommercialPaperMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_3440d49c-6094-468a-ad44-b3626ec9fad1" xlink:to="loc_paa_LineOfCreditAndCommercialPaperMember_8912ef6c-5ee6-40cf-ac10-3ea9c463654a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_7ab54bac-b876-47be-8ce1-60d7ce337445" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_0fef6063-dfe2-403c-a28d-5f55f8ebeb8b" xlink:to="loc_srt_RangeAxis_7ab54bac-b876-47be-8ce1-60d7ce337445" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_7ab54bac-b876-47be-8ce1-60d7ce337445_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_7ab54bac-b876-47be-8ce1-60d7ce337445" xlink:to="loc_srt_RangeMember_7ab54bac-b876-47be-8ce1-60d7ce337445_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_c169b2e9-2fb7-49ab-a3b6-62d09b8bffaf" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_7ab54bac-b876-47be-8ce1-60d7ce337445" xlink:to="loc_srt_RangeMember_c169b2e9-2fb7-49ab-a3b6-62d09b8bffaf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_5e823a49-eca0-476e-aac4-2cff6124fb8a" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_c169b2e9-2fb7-49ab-a3b6-62d09b8bffaf" xlink:to="loc_srt_MaximumMember_5e823a49-eca0-476e-aac4-2cff6124fb8a" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/PartnersCapitalandDistributionsTables" xlink:type="simple" xlink:href="paa-20211231.xsd#PartnersCapitalandDistributionsTables"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/PartnersCapitalandDistributionsTables" xlink:type="extended" id="iafa73525023a46d2acfa29b00b8181c6_PartnersCapitalandDistributionsTables">
    <link:loc xlink:type="locator" xlink:label="loc_paa_PartnersCapitalAndDistributionLineItems_7a0acd87-892a-4403-9acf-c5536c6c543b" xlink:href="paa-20211231.xsd#paa_PartnersCapitalAndDistributionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfStockholdersEquityTableTextBlock_971150ad-59d5-4dae-8a2a-ff2abb061368" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfStockholdersEquityTableTextBlock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_PartnersCapitalAndDistributionLineItems_7a0acd87-892a-4403-9acf-c5536c6c543b" xlink:to="loc_us-gaap_ScheduleOfStockholdersEquityTableTextBlock_971150ad-59d5-4dae-8a2a-ff2abb061368" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DistributionsMadeToLimitedPartnerByDistributionTableTextBlock_6ebb5768-23a3-424c-868a-785923c0d788" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DistributionsMadeToLimitedPartnerByDistributionTableTextBlock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_PartnersCapitalAndDistributionLineItems_7a0acd87-892a-4403-9acf-c5536c6c543b" xlink:to="loc_us-gaap_DistributionsMadeToLimitedPartnerByDistributionTableTextBlock_6ebb5768-23a3-424c-868a-785923c0d788" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PartnersCapitalAndDistributionsTable_d4329601-88c3-4aeb-8fe6-186aa60af238" xlink:href="paa-20211231.xsd#paa_PartnersCapitalAndDistributionsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_paa_PartnersCapitalAndDistributionLineItems_7a0acd87-892a-4403-9acf-c5536c6c543b" xlink:to="loc_paa_PartnersCapitalAndDistributionsTable_d4329601-88c3-4aeb-8fe6-186aa60af238" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_c55492b2-d7c6-4116-9de8-9a9a61f74737" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountByClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_paa_PartnersCapitalAndDistributionsTable_d4329601-88c3-4aeb-8fe6-186aa60af238" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_c55492b2-d7c6-4116-9de8-9a9a61f74737" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_c55492b2-d7c6-4116-9de8-9a9a61f74737_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_c55492b2-d7c6-4116-9de8-9a9a61f74737" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_c55492b2-d7c6-4116-9de8-9a9a61f74737_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_ec2169aa-c426-47ec-a88f-5245cbaeca07" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_c55492b2-d7c6-4116-9de8-9a9a61f74737" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_ec2169aa-c426-47ec-a88f-5245cbaeca07" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SeriesAPreferredUnitsMember_7ab875be-2342-4f4c-aba8-6102c959570d" xlink:href="paa-20211231.xsd#paa_SeriesAPreferredUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_ec2169aa-c426-47ec-a88f-5245cbaeca07" xlink:to="loc_paa_SeriesAPreferredUnitsMember_7ab875be-2342-4f4c-aba8-6102c959570d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeriesBPreferredStockMember_e9ab8576-affd-4379-a85c-ce88c24a0554" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SeriesBPreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_ec2169aa-c426-47ec-a88f-5245cbaeca07" xlink:to="loc_us-gaap_SeriesBPreferredStockMember_e9ab8576-affd-4379-a85c-ce88c24a0554" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_CommonUnitsMember_05026b72-a8ff-4d91-a18a-f92f9135030a" xlink:href="paa-20211231.xsd#paa_CommonUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_ec2169aa-c426-47ec-a88f-5245cbaeca07" xlink:to="loc_paa_CommonUnitsMember_05026b72-a8ff-4d91-a18a-f92f9135030a" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/PartnersCapitalandDistributionsPreferredUnitIssuanceDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#PartnersCapitalandDistributionsPreferredUnitIssuanceDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/PartnersCapitalandDistributionsPreferredUnitIssuanceDetails" xlink:type="extended" id="ied73d5ee4e25463fa02e53da4d71c276_PartnersCapitalandDistributionsPreferredUnitIssuanceDetails">
    <link:loc xlink:type="locator" xlink:label="loc_paa_PartnersCapitalAndDistributionLineItems_33b18199-15d0-4ab1-9c3c-c2d9931c2194" xlink:href="paa-20211231.xsd#paa_PartnersCapitalAndDistributionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesIssuedPricePerShare_5fed0d16-198a-44e5-80f8-e5330de7a41e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SharesIssuedPricePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_PartnersCapitalAndDistributionLineItems_33b18199-15d0-4ab1-9c3c-c2d9931c2194" xlink:to="loc_us-gaap_SharesIssuedPricePerShare_5fed0d16-198a-44e5-80f8-e5330de7a41e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PreferredUnitsQuarterlyDistributionsPerUnit_4cfd0822-975b-45b6-93b9-2b00f52ce630" xlink:href="paa-20211231.xsd#paa_PreferredUnitsQuarterlyDistributionsPerUnit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_PartnersCapitalAndDistributionLineItems_33b18199-15d0-4ab1-9c3c-c2d9931c2194" xlink:to="loc_paa_PreferredUnitsQuarterlyDistributionsPerUnit_4cfd0822-975b-45b6-93b9-2b00f52ce630" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PreferredUnitsAnnualizedDistributionsPerUnit_dedcecfa-6fbc-4331-9fd6-68813817117c" xlink:href="paa-20211231.xsd#paa_PreferredUnitsAnnualizedDistributionsPerUnit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_PartnersCapitalAndDistributionLineItems_33b18199-15d0-4ab1-9c3c-c2d9931c2194" xlink:to="loc_paa_PreferredUnitsAnnualizedDistributionsPerUnit_dedcecfa-6fbc-4331-9fd6-68813817117c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PreferredUnitsConversionRatio_a69770c3-f08e-4b01-b6e4-58b795d51a00" xlink:href="paa-20211231.xsd#paa_PreferredUnitsConversionRatio"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_PartnersCapitalAndDistributionLineItems_33b18199-15d0-4ab1-9c3c-c2d9931c2194" xlink:to="loc_paa_PreferredUnitsConversionRatio_a69770c3-f08e-4b01-b6e4-58b795d51a00" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PreferredUnitsConvertibleThresholdPercentageForCommonUnitPriceTrigger_08f6c294-ac41-4ec9-a105-c65f0d192b7e" xlink:href="paa-20211231.xsd#paa_PreferredUnitsConvertibleThresholdPercentageForCommonUnitPriceTrigger"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_PartnersCapitalAndDistributionLineItems_33b18199-15d0-4ab1-9c3c-c2d9931c2194" xlink:to="loc_paa_PreferredUnitsConvertibleThresholdPercentageForCommonUnitPriceTrigger_08f6c294-ac41-4ec9-a105-c65f0d192b7e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PreferredUnitsConvertibleThresholdConsecutiveTradingDays_18b07aed-8791-4b48-9719-3232c3b76f2b" xlink:href="paa-20211231.xsd#paa_PreferredUnitsConvertibleThresholdConsecutiveTradingDays"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_PartnersCapitalAndDistributionLineItems_33b18199-15d0-4ab1-9c3c-c2d9931c2194" xlink:to="loc_paa_PreferredUnitsConvertibleThresholdConsecutiveTradingDays_18b07aed-8791-4b48-9719-3232c3b76f2b" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PreferredUnitsPeriodAfterFifthAndSubsequentAnniversariesForDistributionRateReset_41830ea1-5570-459d-be50-3d8cee27afec" xlink:href="paa-20211231.xsd#paa_PreferredUnitsPeriodAfterFifthAndSubsequentAnniversariesForDistributionRateReset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_PartnersCapitalAndDistributionLineItems_33b18199-15d0-4ab1-9c3c-c2d9931c2194" xlink:to="loc_paa_PreferredUnitsPeriodAfterFifthAndSubsequentAnniversariesForDistributionRateReset_41830ea1-5570-459d-be50-3d8cee27afec" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PreferredUnitsNumberOfDistributionRateResetElectionsAllowed_5cb266b4-8f23-48e9-9fda-22c21b6a146b" xlink:href="paa-20211231.xsd#paa_PreferredUnitsNumberOfDistributionRateResetElectionsAllowed"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_PartnersCapitalAndDistributionLineItems_33b18199-15d0-4ab1-9c3c-c2d9931c2194" xlink:to="loc_paa_PreferredUnitsNumberOfDistributionRateResetElectionsAllowed_5cb266b4-8f23-48e9-9fda-22c21b6a146b" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PreferredUnitsDistributionRateResetBasisSpreadOnVariableRate_0872872b-d611-4ce6-aa20-c656964eb3f2" xlink:href="paa-20211231.xsd#paa_PreferredUnitsDistributionRateResetBasisSpreadOnVariableRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_PartnersCapitalAndDistributionLineItems_33b18199-15d0-4ab1-9c3c-c2d9931c2194" xlink:to="loc_paa_PreferredUnitsDistributionRateResetBasisSpreadOnVariableRate_0872872b-d611-4ce6-aa20-c656964eb3f2" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PreferredUnitsPeriodAfterSixthAnniversaryForCommencementOfRedemptionOption_1d1a5740-bf1d-45c4-91a7-4c09d96378e1" xlink:href="paa-20211231.xsd#paa_PreferredUnitsPeriodAfterSixthAnniversaryForCommencementOfRedemptionOption"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_PartnersCapitalAndDistributionLineItems_33b18199-15d0-4ab1-9c3c-c2d9931c2194" xlink:to="loc_paa_PreferredUnitsPeriodAfterSixthAnniversaryForCommencementOfRedemptionOption_1d1a5740-bf1d-45c4-91a7-4c09d96378e1" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PreferredUnitRedemptionPercentageOfCommonUnitAveragePrice_a2430781-dde4-495c-a020-1e9a8132d2cd" xlink:href="paa-20211231.xsd#paa_PreferredUnitRedemptionPercentageOfCommonUnitAveragePrice"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_PartnersCapitalAndDistributionLineItems_33b18199-15d0-4ab1-9c3c-c2d9931c2194" xlink:to="loc_paa_PreferredUnitRedemptionPercentageOfCommonUnitAveragePrice_a2430781-dde4-495c-a020-1e9a8132d2cd" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PreferredUnitsRedemptionPriceAsPercentageOfIssuePrice_ee05f78b-fb40-4044-a970-30a39e71b211" xlink:href="paa-20211231.xsd#paa_PreferredUnitsRedemptionPriceAsPercentageOfIssuePrice"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_PartnersCapitalAndDistributionLineItems_33b18199-15d0-4ab1-9c3c-c2d9931c2194" xlink:to="loc_paa_PreferredUnitsRedemptionPriceAsPercentageOfIssuePrice_ee05f78b-fb40-4044-a970-30a39e71b211" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PartnersCapitalAccountSaleOfUnitsPricePerUnit_4ba20bfd-b42e-4184-be2d-c1b6729f4cd3" xlink:href="paa-20211231.xsd#paa_PartnersCapitalAccountSaleOfUnitsPricePerUnit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_PartnersCapitalAndDistributionLineItems_33b18199-15d0-4ab1-9c3c-c2d9931c2194" xlink:to="loc_paa_PartnersCapitalAccountSaleOfUnitsPricePerUnit_4ba20bfd-b42e-4184-be2d-c1b6729f4cd3" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockLiquidationPreference_8420e576-6641-441a-8e72-2a1be19cc98c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PreferredStockLiquidationPreference"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_PartnersCapitalAndDistributionLineItems_33b18199-15d0-4ab1-9c3c-c2d9931c2194" xlink:to="loc_us-gaap_PreferredStockLiquidationPreference_8420e576-6641-441a-8e72-2a1be19cc98c" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockDividendRatePercentage_aa95c08c-e945-4aba-971d-d3d76952e273" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PreferredStockDividendRatePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_PartnersCapitalAndDistributionLineItems_33b18199-15d0-4ab1-9c3c-c2d9931c2194" xlink:to="loc_us-gaap_PreferredStockDividendRatePercentage_aa95c08c-e945-4aba-971d-d3d76952e273" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockDividendRatePerDollarAmount_bb0f7a42-8ad7-44ba-878e-fad5ca6d9c06" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PreferredStockDividendRatePerDollarAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_PartnersCapitalAndDistributionLineItems_33b18199-15d0-4ab1-9c3c-c2d9931c2194" xlink:to="loc_us-gaap_PreferredStockDividendRatePerDollarAmount_bb0f7a42-8ad7-44ba-878e-fad5ca6d9c06" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_DistributionPercentageSpread_18565711-babe-48c9-ab88-cc3483492f8e" xlink:href="paa-20211231.xsd#paa_DistributionPercentageSpread"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_PartnersCapitalAndDistributionLineItems_33b18199-15d0-4ab1-9c3c-c2d9931c2194" xlink:to="loc_paa_DistributionPercentageSpread_18565711-babe-48c9-ab88-cc3483492f8e" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockRedemptionPricePerShare_dea560ec-3235-4d9d-91e2-4febd24c2f3d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PreferredStockRedemptionPricePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_PartnersCapitalAndDistributionLineItems_33b18199-15d0-4ab1-9c3c-c2d9931c2194" xlink:to="loc_us-gaap_PreferredStockRedemptionPricePerShare_dea560ec-3235-4d9d-91e2-4febd24c2f3d" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PreferredStockRedemptionPricePercentage_2ce85df1-97c5-4bae-9618-b76c93e6c23b" xlink:href="paa-20211231.xsd#paa_PreferredStockRedemptionPricePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_PartnersCapitalAndDistributionLineItems_33b18199-15d0-4ab1-9c3c-c2d9931c2194" xlink:to="loc_paa_PreferredStockRedemptionPricePercentage_2ce85df1-97c5-4bae-9618-b76c93e6c23b" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PartnersCapitalAndDistributionsTable_ec533aa2-292e-4b9f-9ece-c335901f42e4" xlink:href="paa-20211231.xsd#paa_PartnersCapitalAndDistributionsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_paa_PartnersCapitalAndDistributionLineItems_33b18199-15d0-4ab1-9c3c-c2d9931c2194" xlink:to="loc_paa_PartnersCapitalAndDistributionsTable_ec533aa2-292e-4b9f-9ece-c335901f42e4" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_e69c2d20-062e-42b1-b491-a279b4ec7985" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountByClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_paa_PartnersCapitalAndDistributionsTable_ec533aa2-292e-4b9f-9ece-c335901f42e4" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_e69c2d20-062e-42b1-b491-a279b4ec7985" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_e69c2d20-062e-42b1-b491-a279b4ec7985_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_e69c2d20-062e-42b1-b491-a279b4ec7985" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_e69c2d20-062e-42b1-b491-a279b4ec7985_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_5ac31fc7-a113-4f6c-9ea3-de1e0f17ebb1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_e69c2d20-062e-42b1-b491-a279b4ec7985" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_5ac31fc7-a113-4f6c-9ea3-de1e0f17ebb1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SeriesAPreferredUnitsMember_23c3dbfe-13cb-4b71-9c47-6ba9e7e7095c" xlink:href="paa-20211231.xsd#paa_SeriesAPreferredUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_5ac31fc7-a113-4f6c-9ea3-de1e0f17ebb1" xlink:to="loc_paa_SeriesAPreferredUnitsMember_23c3dbfe-13cb-4b71-9c47-6ba9e7e7095c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeriesBPreferredStockMember_da206bde-91bb-491d-a026-62ebee600d3e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SeriesBPreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_5ac31fc7-a113-4f6c-9ea3-de1e0f17ebb1" xlink:to="loc_us-gaap_SeriesBPreferredStockMember_da206bde-91bb-491d-a026-62ebee600d3e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementScenarioAxis_e6a48cf1-bc08-4937-b83e-e12d9f25a90d" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_StatementScenarioAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_paa_PartnersCapitalAndDistributionsTable_ec533aa2-292e-4b9f-9ece-c335901f42e4" xlink:to="loc_srt_StatementScenarioAxis_e6a48cf1-bc08-4937-b83e-e12d9f25a90d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioUnspecifiedDomain_e6a48cf1-bc08-4937-b83e-e12d9f25a90d_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ScenarioUnspecifiedDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementScenarioAxis_e6a48cf1-bc08-4937-b83e-e12d9f25a90d" xlink:to="loc_srt_ScenarioUnspecifiedDomain_e6a48cf1-bc08-4937-b83e-e12d9f25a90d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioUnspecifiedDomain_ae771288-7a78-47ac-a2d4-b09deeeea945" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ScenarioUnspecifiedDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementScenarioAxis_e6a48cf1-bc08-4937-b83e-e12d9f25a90d" xlink:to="loc_srt_ScenarioUnspecifiedDomain_ae771288-7a78-47ac-a2d4-b09deeeea945" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioForecastMember_2a87c1ad-ec1c-4a0c-8833-4f1648703d0c" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ScenarioForecastMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ScenarioUnspecifiedDomain_ae771288-7a78-47ac-a2d4-b09deeeea945" xlink:to="loc_srt_ScenarioForecastMember_2a87c1ad-ec1c-4a0c-8833-4f1648703d0c" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/PartnersCapitalandDistributionsActivityforSeriesAandBPreferredUnitsandCommonUnitsDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#PartnersCapitalandDistributionsActivityforSeriesAandBPreferredUnitsandCommonUnitsDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/PartnersCapitalandDistributionsActivityforSeriesAandBPreferredUnitsandCommonUnitsDetails" xlink:type="extended" id="i206d931d0492479e9a233fec752804ef_PartnersCapitalandDistributionsActivityforSeriesAandBPreferredUnitsandCommonUnitsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_paa_PartnersCapitalAndDistributionLineItems_3f7ba59f-486b-4966-8eb5-4f55089bc90d" xlink:href="paa-20211231.xsd#paa_PartnersCapitalAndDistributionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_b76e48dd-7a24-4329-82f8-266482b25478" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInPartnersCapitalRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_PartnersCapitalAndDistributionLineItems_3f7ba59f-486b-4966-8eb5-4f55089bc90d" xlink:to="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_b76e48dd-7a24-4329-82f8-266482b25478" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountUnitsOutstanding_e37a0d89-c41a-4526-a1c4-8c7fa6a3aabf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountUnitsOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_b76e48dd-7a24-4329-82f8-266482b25478" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountUnitsOutstanding_e37a0d89-c41a-4526-a1c4-8c7fa6a3aabf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_0c089802-897c-4526-80d1-23b80501683e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_b76e48dd-7a24-4329-82f8-266482b25478" xlink:to="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_0c089802-897c-4526-80d1-23b80501683e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapitalAccountUnitsUnitbasedCompensation_5272370a-a0c7-46df-ba9a-8cba255b0192" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnersCapitalAccountUnitsUnitbasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_b76e48dd-7a24-4329-82f8-266482b25478" xlink:to="loc_us-gaap_PartnersCapitalAccountUnitsUnitbasedCompensation_5272370a-a0c7-46df-ba9a-8cba255b0192" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountUnitsOutstanding_cf28fbfe-ad8c-40f6-86cd-30c5ddb24fbd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountUnitsOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PartnersCapitalAndDistributionsTable_0e8f8779-53e3-4591-82c3-5af016811dea" xlink:href="paa-20211231.xsd#paa_PartnersCapitalAndDistributionsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_paa_PartnersCapitalAndDistributionLineItems_3f7ba59f-486b-4966-8eb5-4f55089bc90d" xlink:to="loc_paa_PartnersCapitalAndDistributionsTable_0e8f8779-53e3-4591-82c3-5af016811dea" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_bc5fc274-2a7e-4bc8-bee0-753706759e5e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_paa_PartnersCapitalAndDistributionsTable_0e8f8779-53e3-4591-82c3-5af016811dea" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_bc5fc274-2a7e-4bc8-bee0-753706759e5e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_bc5fc274-2a7e-4bc8-bee0-753706759e5e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_bc5fc274-2a7e-4bc8-bee0-753706759e5e" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_bc5fc274-2a7e-4bc8-bee0-753706759e5e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_cb702734-bf5a-4813-b388-bbdfc36b7fcd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_bc5fc274-2a7e-4bc8-bee0-753706759e5e" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_cb702734-bf5a-4813-b388-bbdfc36b7fcd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnerMember_71defb9d-b5c5-425e-a09f-978b3add4745" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_cb702734-bf5a-4813-b388-bbdfc36b7fcd" xlink:to="loc_us-gaap_LimitedPartnerMember_71defb9d-b5c5-425e-a09f-978b3add4745" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_1a47d15e-7eef-4725-a18b-5a20da8bd441" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountByClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_paa_PartnersCapitalAndDistributionsTable_0e8f8779-53e3-4591-82c3-5af016811dea" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_1a47d15e-7eef-4725-a18b-5a20da8bd441" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_1a47d15e-7eef-4725-a18b-5a20da8bd441_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_1a47d15e-7eef-4725-a18b-5a20da8bd441" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_1a47d15e-7eef-4725-a18b-5a20da8bd441_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_b6ec8603-91a8-4127-ac00-97ee46f7e95c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_1a47d15e-7eef-4725-a18b-5a20da8bd441" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_b6ec8603-91a8-4127-ac00-97ee46f7e95c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SeriesAPreferredUnitsMember_0f6ee245-8c6a-4e30-b231-4b3bbfadeb54" xlink:href="paa-20211231.xsd#paa_SeriesAPreferredUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_b6ec8603-91a8-4127-ac00-97ee46f7e95c" xlink:to="loc_paa_SeriesAPreferredUnitsMember_0f6ee245-8c6a-4e30-b231-4b3bbfadeb54" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SeriesBPreferredUnitsMember_d90f7c95-c022-4431-9511-dce2edade95d" xlink:href="paa-20211231.xsd#paa_SeriesBPreferredUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_b6ec8603-91a8-4127-ac00-97ee46f7e95c" xlink:to="loc_paa_SeriesBPreferredUnitsMember_d90f7c95-c022-4431-9511-dce2edade95d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_CommonUnitsMember_e7ffb3f6-219a-4854-a534-c6a5ea60808f" xlink:href="paa-20211231.xsd#paa_CommonUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_b6ec8603-91a8-4127-ac00-97ee46f7e95c" xlink:to="loc_paa_CommonUnitsMember_e7ffb3f6-219a-4854-a534-c6a5ea60808f" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/PartnersCapitalandDistributionsCommonEquityRepurchaseProgramDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#PartnersCapitalandDistributionsCommonEquityRepurchaseProgramDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/PartnersCapitalandDistributionsCommonEquityRepurchaseProgramDetails" xlink:type="extended" id="ibf16a10a51ab4d38a35a2b5c02661e27_PartnersCapitalandDistributionsCommonEquityRepurchaseProgramDetails">
    <link:loc xlink:type="locator" xlink:label="loc_paa_PartnersCapitalAndDistributionLineItems_e02504cd-8586-453a-af42-b8c2247a6bc6" xlink:href="paa-20211231.xsd#paa_PartnersCapitalAndDistributionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchaseProgramAuthorizedAmount1_319d8b05-2f6c-4230-b8d3-b095d885fc8a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockRepurchaseProgramAuthorizedAmount1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_PartnersCapitalAndDistributionLineItems_e02504cd-8586-453a-af42-b8c2247a6bc6" xlink:to="loc_us-gaap_StockRepurchaseProgramAuthorizedAmount1_319d8b05-2f6c-4230-b8d3-b095d885fc8a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_92ffc879-6b4a-4e60-aa7e-a05fdc9b92ac" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_PartnersCapitalAndDistributionLineItems_e02504cd-8586-453a-af42-b8c2247a6bc6" xlink:to="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_92ffc879-6b4a-4e60-aa7e-a05fdc9b92ac" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodValue_61008d0b-3423-421c-a4ec-79a3ff7eb679" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_PartnersCapitalAndDistributionLineItems_e02504cd-8586-453a-af42-b8c2247a6bc6" xlink:to="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodValue_61008d0b-3423-421c-a4ec-79a3ff7eb679" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1_71437044-0711-425f-b977-8471344afc82" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_PartnersCapitalAndDistributionLineItems_e02504cd-8586-453a-af42-b8c2247a6bc6" xlink:to="loc_us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1_71437044-0711-425f-b977-8471344afc82" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PartnersCapitalAndDistributionsTable_33fdf275-bf10-44b0-900d-97ab38fb377e" xlink:href="paa-20211231.xsd#paa_PartnersCapitalAndDistributionsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_paa_PartnersCapitalAndDistributionLineItems_e02504cd-8586-453a-af42-b8c2247a6bc6" xlink:to="loc_paa_PartnersCapitalAndDistributionsTable_33fdf275-bf10-44b0-900d-97ab38fb377e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareRepurchaseProgramAxis_8b54edd3-18fa-47a1-9eba-a487bf4c18ad" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareRepurchaseProgramAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_paa_PartnersCapitalAndDistributionsTable_33fdf275-bf10-44b0-900d-97ab38fb377e" xlink:to="loc_us-gaap_ShareRepurchaseProgramAxis_8b54edd3-18fa-47a1-9eba-a487bf4c18ad" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareRepurchaseProgramDomain_8b54edd3-18fa-47a1-9eba-a487bf4c18ad_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareRepurchaseProgramDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShareRepurchaseProgramAxis_8b54edd3-18fa-47a1-9eba-a487bf4c18ad" xlink:to="loc_us-gaap_ShareRepurchaseProgramDomain_8b54edd3-18fa-47a1-9eba-a487bf4c18ad_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareRepurchaseProgramDomain_0e79e201-2f21-49e7-8231-194a7c0012b1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareRepurchaseProgramDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShareRepurchaseProgramAxis_8b54edd3-18fa-47a1-9eba-a487bf4c18ad" xlink:to="loc_us-gaap_ShareRepurchaseProgramDomain_0e79e201-2f21-49e7-8231-194a7c0012b1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_CommonEquityRepurchaseProgramMember_0998fb3d-fe4c-4c0b-a302-e176a68925e4" xlink:href="paa-20211231.xsd#paa_CommonEquityRepurchaseProgramMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareRepurchaseProgramDomain_0e79e201-2f21-49e7-8231-194a7c0012b1" xlink:to="loc_paa_CommonEquityRepurchaseProgramMember_0998fb3d-fe4c-4c0b-a302-e176a68925e4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_436df066-66ac-4c53-a902-38aaf4b795e6" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_paa_PartnersCapitalAndDistributionsTable_33fdf275-bf10-44b0-900d-97ab38fb377e" xlink:to="loc_srt_RangeAxis_436df066-66ac-4c53-a902-38aaf4b795e6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_436df066-66ac-4c53-a902-38aaf4b795e6_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_436df066-66ac-4c53-a902-38aaf4b795e6" xlink:to="loc_srt_RangeMember_436df066-66ac-4c53-a902-38aaf4b795e6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_05b9a6bf-95f3-4f3c-b982-70c92e370aba" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_436df066-66ac-4c53-a902-38aaf4b795e6" xlink:to="loc_srt_RangeMember_05b9a6bf-95f3-4f3c-b982-70c92e370aba" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_c916496c-6886-43cb-a995-f10dd5e23069" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_05b9a6bf-95f3-4f3c-b982-70c92e370aba" xlink:to="loc_srt_MaximumMember_c916496c-6886-43cb-a995-f10dd5e23069" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/PartnersCapitalandDistributionsPreferredUnitDistributionsDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#PartnersCapitalandDistributionsPreferredUnitDistributionsDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/PartnersCapitalandDistributionsPreferredUnitDistributionsDetails" xlink:type="extended" id="i7af333a18da44384a3280b75e6a14f87_PartnersCapitalandDistributionsPreferredUnitDistributionsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_paa_PartnersCapitalAndDistributionLineItems_1c0ceeee-1858-428a-bcfa-c6a79e51d1ad" xlink:href="paa-20211231.xsd#paa_PartnersCapitalAndDistributionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_NumberOfDaysRequiredForDistributionToUnitholdersAfterEndOfQuarter_3df5e6f7-ca01-4f32-994c-dfb9c3280c3f" xlink:href="paa-20211231.xsd#paa_NumberOfDaysRequiredForDistributionToUnitholdersAfterEndOfQuarter"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_PartnersCapitalAndDistributionLineItems_1c0ceeee-1858-428a-bcfa-c6a79e51d1ad" xlink:to="loc_paa_NumberOfDaysRequiredForDistributionToUnitholdersAfterEndOfQuarter_3df5e6f7-ca01-4f32-994c-dfb9c3280c3f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsPreferredStock_e5c61cb2-f345-4440-8e0a-b3afd23e27b8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DividendsPreferredStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_PartnersCapitalAndDistributionLineItems_1c0ceeee-1858-428a-bcfa-c6a79e51d1ad" xlink:to="loc_us-gaap_DividendsPreferredStock_e5c61cb2-f345-4440-8e0a-b3afd23e27b8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsPayableCurrentAndNoncurrent_c95259cb-0fd6-4a57-8157-4235cbb655a5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DividendsPayableCurrentAndNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_PartnersCapitalAndDistributionLineItems_1c0ceeee-1858-428a-bcfa-c6a79e51d1ad" xlink:to="loc_us-gaap_DividendsPayableCurrentAndNoncurrent_c95259cb-0fd6-4a57-8157-4235cbb655a5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PartnersCapitalAndDistributionsTable_a6e5c8f0-5eae-45b9-aef5-c8d7fd72548c" xlink:href="paa-20211231.xsd#paa_PartnersCapitalAndDistributionsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_paa_PartnersCapitalAndDistributionLineItems_1c0ceeee-1858-428a-bcfa-c6a79e51d1ad" xlink:to="loc_paa_PartnersCapitalAndDistributionsTable_a6e5c8f0-5eae-45b9-aef5-c8d7fd72548c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_4eb3a5ca-6073-4d9c-9c42-3b9b14702279" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_paa_PartnersCapitalAndDistributionsTable_a6e5c8f0-5eae-45b9-aef5-c8d7fd72548c" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_4eb3a5ca-6073-4d9c-9c42-3b9b14702279" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_4eb3a5ca-6073-4d9c-9c42-3b9b14702279_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_4eb3a5ca-6073-4d9c-9c42-3b9b14702279" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_4eb3a5ca-6073-4d9c-9c42-3b9b14702279_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_3f4bb6dd-b36b-42de-8549-cdfa1e8aeb98" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_4eb3a5ca-6073-4d9c-9c42-3b9b14702279" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_3f4bb6dd-b36b-42de-8549-cdfa1e8aeb98" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCurrentLiabilitiesMember_95ddb5ca-32b7-44bb-a871-e029252397df" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherCurrentLiabilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_3f4bb6dd-b36b-42de-8549-cdfa1e8aeb98" xlink:to="loc_us-gaap_OtherCurrentLiabilitiesMember_95ddb5ca-32b7-44bb-a871-e029252397df" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_541939f3-f9b0-464a-a6bd-4e8233dc5c01" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_paa_PartnersCapitalAndDistributionsTable_a6e5c8f0-5eae-45b9-aef5-c8d7fd72548c" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_541939f3-f9b0-464a-a6bd-4e8233dc5c01" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_541939f3-f9b0-464a-a6bd-4e8233dc5c01_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_541939f3-f9b0-464a-a6bd-4e8233dc5c01" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_541939f3-f9b0-464a-a6bd-4e8233dc5c01_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_a03cf49f-2167-4519-857a-5b3df113e00d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_541939f3-f9b0-464a-a6bd-4e8233dc5c01" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_a03cf49f-2167-4519-857a-5b3df113e00d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_e0d5830c-964d-49d9-9f6c-249f863eb94f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_a03cf49f-2167-4519-857a-5b3df113e00d" xlink:to="loc_us-gaap_SubsequentEventMember_e0d5830c-964d-49d9-9f6c-249f863eb94f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_b1308af1-fc78-4eee-acd6-8dc1fe71f3af" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_paa_PartnersCapitalAndDistributionsTable_a6e5c8f0-5eae-45b9-aef5-c8d7fd72548c" xlink:to="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_b1308af1-fc78-4eee-acd6-8dc1fe71f3af" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DistributionTypeDomain_b1308af1-fc78-4eee-acd6-8dc1fe71f3af_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DistributionTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_b1308af1-fc78-4eee-acd6-8dc1fe71f3af" xlink:to="loc_us-gaap_DistributionTypeDomain_b1308af1-fc78-4eee-acd6-8dc1fe71f3af_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DistributionTypeDomain_0ed1fe11-7f9a-4909-a90a-48bf156aa66c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DistributionTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_b1308af1-fc78-4eee-acd6-8dc1fe71f3af" xlink:to="loc_us-gaap_DistributionTypeDomain_0ed1fe11-7f9a-4909-a90a-48bf156aa66c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashDistributionMember_68d82431-2d19-450b-ac43-165a1a2c54f2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashDistributionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DistributionTypeDomain_0ed1fe11-7f9a-4909-a90a-48bf156aa66c" xlink:to="loc_us-gaap_CashDistributionMember_68d82431-2d19-450b-ac43-165a1a2c54f2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_10ac3543-afba-4466-ba57-5134df0d3bda" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountByClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_paa_PartnersCapitalAndDistributionsTable_a6e5c8f0-5eae-45b9-aef5-c8d7fd72548c" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_10ac3543-afba-4466-ba57-5134df0d3bda" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_10ac3543-afba-4466-ba57-5134df0d3bda_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_10ac3543-afba-4466-ba57-5134df0d3bda" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_10ac3543-afba-4466-ba57-5134df0d3bda_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_19c5e49f-2e92-470f-afcf-5ec68529397a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_10ac3543-afba-4466-ba57-5134df0d3bda" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_19c5e49f-2e92-470f-afcf-5ec68529397a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SeriesAPreferredUnitsMember_8d528544-5f85-47bd-a97a-ff424894b592" xlink:href="paa-20211231.xsd#paa_SeriesAPreferredUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_19c5e49f-2e92-470f-afcf-5ec68529397a" xlink:to="loc_paa_SeriesAPreferredUnitsMember_8d528544-5f85-47bd-a97a-ff424894b592" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeriesBPreferredStockMember_0b83c071-f624-4564-8f7d-c71d34e21581" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SeriesBPreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_19c5e49f-2e92-470f-afcf-5ec68529397a" xlink:to="loc_us-gaap_SeriesBPreferredStockMember_0b83c071-f624-4564-8f7d-c71d34e21581" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/PartnersCapitalandDistributionsCommonUnitDistributionsDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#PartnersCapitalandDistributionsCommonUnitDistributionsDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/PartnersCapitalandDistributionsCommonUnitDistributionsDetails" xlink:type="extended" id="i3a1743de75fb4a78bf4d7809d57260c3_PartnersCapitalandDistributionsCommonUnitDistributionsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DistributionMadeToLimitedPartnerLineItems_80eddfc5-2387-4eea-a9bc-7e69854594d0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DistributionMadeToLimitedPartnerLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountDistributionAmount_76b571c3-c1f4-4774-a341-1025352b0c8b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountDistributionAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DistributionMadeToLimitedPartnerLineItems_80eddfc5-2387-4eea-a9bc-7e69854594d0" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountDistributionAmount_76b571c3-c1f4-4774-a341-1025352b0c8b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DistributionMadeToLimitedPartnerDistributionsPaidPerUnit_b0e6981c-3ecc-4649-beae-890374d283e7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DistributionMadeToLimitedPartnerDistributionsPaidPerUnit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DistributionMadeToLimitedPartnerLineItems_80eddfc5-2387-4eea-a9bc-7e69854594d0" xlink:to="loc_us-gaap_DistributionMadeToLimitedPartnerDistributionsPaidPerUnit_b0e6981c-3ecc-4649-beae-890374d283e7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DistributionMadeToLimitedPartnerDistributionsDeclaredPerUnit_fe89c27a-2489-4cc2-abb4-81f63a313802" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DistributionMadeToLimitedPartnerDistributionsDeclaredPerUnit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DistributionMadeToLimitedPartnerLineItems_80eddfc5-2387-4eea-a9bc-7e69854594d0" xlink:to="loc_us-gaap_DistributionMadeToLimitedPartnerDistributionsDeclaredPerUnit_fe89c27a-2489-4cc2-abb4-81f63a313802" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DistributionsMadeToLimitedPartnerTable_ac956266-dc34-4209-989e-4f009bffb5e3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DistributionsMadeToLimitedPartnerTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DistributionMadeToLimitedPartnerLineItems_80eddfc5-2387-4eea-a9bc-7e69854594d0" xlink:to="loc_us-gaap_DistributionsMadeToLimitedPartnerTable_ac956266-dc34-4209-989e-4f009bffb5e3" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsAxis_ca846aaa-c7da-4d94-a2da-0ac3e3e30798" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DividendsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DistributionsMadeToLimitedPartnerTable_ac956266-dc34-4209-989e-4f009bffb5e3" xlink:to="loc_us-gaap_DividendsAxis_ca846aaa-c7da-4d94-a2da-0ac3e3e30798" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsDomain_ca846aaa-c7da-4d94-a2da-0ac3e3e30798_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DividendsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DividendsAxis_ca846aaa-c7da-4d94-a2da-0ac3e3e30798" xlink:to="loc_us-gaap_DividendsDomain_ca846aaa-c7da-4d94-a2da-0ac3e3e30798_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsDomain_612ca030-aab2-48db-b2c0-dfffa0f9d8f7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DividendsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DividendsAxis_ca846aaa-c7da-4d94-a2da-0ac3e3e30798" xlink:to="loc_us-gaap_DividendsDomain_612ca030-aab2-48db-b2c0-dfffa0f9d8f7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_FourthQuarterDistributionMember_f161a280-841d-424c-9e4d-bb8469fc54e5" xlink:href="paa-20211231.xsd#paa_FourthQuarterDistributionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DividendsDomain_612ca030-aab2-48db-b2c0-dfffa0f9d8f7" xlink:to="loc_paa_FourthQuarterDistributionMember_f161a280-841d-424c-9e4d-bb8469fc54e5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_26bcfdb8-800f-4bc8-ab30-890fa381d224" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DistributionsMadeToLimitedPartnerTable_ac956266-dc34-4209-989e-4f009bffb5e3" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_26bcfdb8-800f-4bc8-ab30-890fa381d224" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_26bcfdb8-800f-4bc8-ab30-890fa381d224_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_26bcfdb8-800f-4bc8-ab30-890fa381d224" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_26bcfdb8-800f-4bc8-ab30-890fa381d224_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_0ff6a6dd-15b6-45fc-b3af-af160b30e6d1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_26bcfdb8-800f-4bc8-ab30-890fa381d224" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_0ff6a6dd-15b6-45fc-b3af-af160b30e6d1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_87f43791-bed9-4d83-87b7-2508e0a20740" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_0ff6a6dd-15b6-45fc-b3af-af160b30e6d1" xlink:to="loc_us-gaap_SubsequentEventMember_87f43791-bed9-4d83-87b7-2508e0a20740" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_bbbb3222-8797-4f44-aaf2-8b785760a29c" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DistributionsMadeToLimitedPartnerTable_ac956266-dc34-4209-989e-4f009bffb5e3" xlink:to="loc_srt_CounterpartyNameAxis_bbbb3222-8797-4f44-aaf2-8b785760a29c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_bbbb3222-8797-4f44-aaf2-8b785760a29c_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_bbbb3222-8797-4f44-aaf2-8b785760a29c" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_bbbb3222-8797-4f44-aaf2-8b785760a29c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_58485bc8-0ba6-4204-a6b5-5c8bc3f6db45" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_bbbb3222-8797-4f44-aaf2-8b785760a29c" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_58485bc8-0ba6-4204-a6b5-5c8bc3f6db45" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PublicUnitHoldersMember_f6cc2b65-7dd5-4c0f-9253-785f35496b03" xlink:href="paa-20211231.xsd#paa_PublicUnitHoldersMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_58485bc8-0ba6-4204-a6b5-5c8bc3f6db45" xlink:to="loc_paa_PublicUnitHoldersMember_f6cc2b65-7dd5-4c0f-9253-785f35496b03" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PlainsAapLPMember_f7be646b-cd5c-406c-bf80-5ebe27434c3f" xlink:href="paa-20211231.xsd#paa_PlainsAapLPMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_58485bc8-0ba6-4204-a6b5-5c8bc3f6db45" xlink:to="loc_paa_PlainsAapLPMember_f7be646b-cd5c-406c-bf80-5ebe27434c3f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_99fc5184-696a-4d86-9342-cec08b2bba1f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountByClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DistributionsMadeToLimitedPartnerTable_ac956266-dc34-4209-989e-4f009bffb5e3" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_99fc5184-696a-4d86-9342-cec08b2bba1f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_99fc5184-696a-4d86-9342-cec08b2bba1f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_99fc5184-696a-4d86-9342-cec08b2bba1f" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_99fc5184-696a-4d86-9342-cec08b2bba1f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_3f2afd32-ab03-44b1-9cd1-4b0a12797913" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_99fc5184-696a-4d86-9342-cec08b2bba1f" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_3f2afd32-ab03-44b1-9cd1-4b0a12797913" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_CommonUnitsMember_e5755dc7-260f-4c98-8295-66424efb18f8" xlink:href="paa-20211231.xsd#paa_CommonUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_3f2afd32-ab03-44b1-9cd1-4b0a12797913" xlink:to="loc_paa_CommonUnitsMember_e5755dc7-260f-4c98-8295-66424efb18f8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_7529a3c9-3dbb-4cf1-a57f-d49cf8d654b2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DistributionsMadeToLimitedPartnerTable_ac956266-dc34-4209-989e-4f009bffb5e3" xlink:to="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_7529a3c9-3dbb-4cf1-a57f-d49cf8d654b2" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DistributionTypeDomain_7529a3c9-3dbb-4cf1-a57f-d49cf8d654b2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DistributionTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_7529a3c9-3dbb-4cf1-a57f-d49cf8d654b2" xlink:to="loc_us-gaap_DistributionTypeDomain_7529a3c9-3dbb-4cf1-a57f-d49cf8d654b2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DistributionTypeDomain_f9c8d66f-2c9f-4654-8a03-9b52812ec39d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DistributionTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_7529a3c9-3dbb-4cf1-a57f-d49cf8d654b2" xlink:to="loc_us-gaap_DistributionTypeDomain_f9c8d66f-2c9f-4654-8a03-9b52812ec39d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashDistributionMember_b94aea8f-e25b-4be7-9799-7a717e9728b0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashDistributionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DistributionTypeDomain_f9c8d66f-2c9f-4654-8a03-9b52812ec39d" xlink:to="loc_us-gaap_CashDistributionMember_b94aea8f-e25b-4be7-9799-7a717e9728b0" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/PartnersCapitalandDistributionsNoncontrollingInterestsinSubsidiariesDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#PartnersCapitalandDistributionsNoncontrollingInterestsinSubsidiariesDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/PartnersCapitalandDistributionsNoncontrollingInterestsinSubsidiariesDetails" xlink:type="extended" id="i2f84cff0e3c1449294d8dca3aa13a6bc_PartnersCapitalandDistributionsNoncontrollingInterestsinSubsidiariesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_paa_PartnersCapitalAndDistributionLineItems_f647fcff-d688-4855-a871-8cb5a17333a8" xlink:href="paa-20211231.xsd#paa_PartnersCapitalAndDistributionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestOwnershipPercentageByParent_df9b3706-84b9-4575-8430-7155d09ecf1d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MinorityInterestOwnershipPercentageByParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_PartnersCapitalAndDistributionLineItems_f647fcff-d688-4855-a871-8cb5a17333a8" xlink:to="loc_us-gaap_MinorityInterestOwnershipPercentageByParent_df9b3706-84b9-4575-8430-7155d09ecf1d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners_61d7a843-8da1-4eeb-b29d-e3a8bc61ab6a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_PartnersCapitalAndDistributionLineItems_f647fcff-d688-4855-a871-8cb5a17333a8" xlink:to="loc_us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners_61d7a843-8da1-4eeb-b29d-e3a8bc61ab6a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipOwnershipInterest_a8222830-837b-4196-9972-787a2b1870c0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipOwnershipInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_PartnersCapitalAndDistributionLineItems_f647fcff-d688-4855-a871-8cb5a17333a8" xlink:to="loc_us-gaap_SubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipOwnershipInterest_a8222830-837b-4196-9972-787a2b1870c0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapitalAttributableToNoncontrollingInterest_71be0e65-f787-4e13-80b9-71e7150a3956" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnersCapitalAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_PartnersCapitalAndDistributionLineItems_f647fcff-d688-4855-a871-8cb5a17333a8" xlink:to="loc_us-gaap_PartnersCapitalAttributableToNoncontrollingInterest_71be0e65-f787-4e13-80b9-71e7150a3956" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapital_b4ac7220-cd3f-4277-8711-2cbb8c737636" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnersCapital"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_PartnersCapitalAndDistributionLineItems_f647fcff-d688-4855-a871-8cb5a17333a8" xlink:to="loc_us-gaap_PartnersCapital_b4ac7220-cd3f-4277-8711-2cbb8c737636" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromMinorityShareholders_de1d1138-0f27-4877-951f-4ae2a92b4113" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromMinorityShareholders"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_PartnersCapitalAndDistributionLineItems_f647fcff-d688-4855-a871-8cb5a17333a8" xlink:to="loc_us-gaap_ProceedsFromMinorityShareholders_de1d1138-0f27-4877-951f-4ae2a92b4113" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapitalAccountContributions_e51b1147-d7fb-4b31-bee2-b4bde1c8fbc3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnersCapitalAccountContributions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_PartnersCapitalAndDistributionLineItems_f647fcff-d688-4855-a871-8cb5a17333a8" xlink:to="loc_us-gaap_PartnersCapitalAccountContributions_e51b1147-d7fb-4b31-bee2-b4bde1c8fbc3" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapitalAccountDistributions_5457c118-64f0-4b9b-8f99-5edb332eeeeb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnersCapitalAccountDistributions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_PartnersCapitalAndDistributionLineItems_f647fcff-d688-4855-a871-8cb5a17333a8" xlink:to="loc_us-gaap_PartnersCapitalAccountDistributions_5457c118-64f0-4b9b-8f99-5edb332eeeeb" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PartnersCapitalAndDistributionsTable_164d482d-e036-4e85-9ec0-94eb3be20d9e" xlink:href="paa-20211231.xsd#paa_PartnersCapitalAndDistributionsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_paa_PartnersCapitalAndDistributionLineItems_f647fcff-d688-4855-a871-8cb5a17333a8" xlink:to="loc_paa_PartnersCapitalAndDistributionsTable_164d482d-e036-4e85-9ec0-94eb3be20d9e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_78917614-c650-4a2e-9809-c2525e48e4f6" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_paa_PartnersCapitalAndDistributionsTable_164d482d-e036-4e85-9ec0-94eb3be20d9e" xlink:to="loc_dei_LegalEntityAxis_78917614-c650-4a2e-9809-c2525e48e4f6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_78917614-c650-4a2e-9809-c2525e48e4f6_default" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_78917614-c650-4a2e-9809-c2525e48e4f6" xlink:to="loc_dei_EntityDomain_78917614-c650-4a2e-9809-c2525e48e4f6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_7cdb3d3e-64fb-4d15-99c0-4fc230e5b141" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_78917614-c650-4a2e-9809-c2525e48e4f6" xlink:to="loc_dei_EntityDomain_7cdb3d3e-64fb-4d15-99c0-4fc230e5b141" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_RedRiverPipelineCompanyLLCMember_eab9fea2-f31b-4e58-80d7-19cdd4e4fea2" xlink:href="paa-20211231.xsd#paa_RedRiverPipelineCompanyLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7cdb3d3e-64fb-4d15-99c0-4fc230e5b141" xlink:to="loc_paa_RedRiverPipelineCompanyLLCMember_eab9fea2-f31b-4e58-80d7-19cdd4e4fea2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PlainsOryxPermianBasinLLCMember_3e6d1a93-342c-4a0a-ac8d-5d38b793c4a2" xlink:href="paa-20211231.xsd#paa_PlainsOryxPermianBasinLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7cdb3d3e-64fb-4d15-99c0-4fc230e5b141" xlink:to="loc_paa_PlainsOryxPermianBasinLLCMember_3e6d1a93-342c-4a0a-ac8d-5d38b793c4a2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipAxis_ef5bd499-380d-41da-a679-6c419a90f200" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_OwnershipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_paa_PartnersCapitalAndDistributionsTable_164d482d-e036-4e85-9ec0-94eb3be20d9e" xlink:to="loc_srt_OwnershipAxis_ef5bd499-380d-41da-a679-6c419a90f200" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_ef5bd499-380d-41da-a679-6c419a90f200_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_OwnershipAxis_ef5bd499-380d-41da-a679-6c419a90f200" xlink:to="loc_srt_OwnershipDomain_ef5bd499-380d-41da-a679-6c419a90f200_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_ff340ceb-671c-4001-8f6f-4af6ac6c1c2c" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_OwnershipAxis_ef5bd499-380d-41da-a679-6c419a90f200" xlink:to="loc_srt_OwnershipDomain_ff340ceb-671c-4001-8f6f-4af6ac6c1c2c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PlainsOryxPermianBasinLLCMember_c789f3e9-fd24-4610-82b4-7038d950eb52" xlink:href="paa-20211231.xsd#paa_PlainsOryxPermianBasinLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_OwnershipDomain_ff340ceb-671c-4001-8f6f-4af6ac6c1c2c" xlink:to="loc_paa_PlainsOryxPermianBasinLLCMember_c789f3e9-fd24-4610-82b4-7038d950eb52" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_RedRiverPipelineCompanyLLCMember_1bbe9754-85b2-4eb9-ad32-e15418989711" xlink:href="paa-20211231.xsd#paa_RedRiverPipelineCompanyLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_OwnershipDomain_ff340ceb-671c-4001-8f6f-4af6ac6c1c2c" xlink:to="loc_paa_RedRiverPipelineCompanyLLCMember_1bbe9754-85b2-4eb9-ad32-e15418989711" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_9356586b-c855-46c6-a2a9-7861bbd5a660" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_paa_PartnersCapitalAndDistributionsTable_164d482d-e036-4e85-9ec0-94eb3be20d9e" xlink:to="loc_srt_CounterpartyNameAxis_9356586b-c855-46c6-a2a9-7861bbd5a660" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_9356586b-c855-46c6-a2a9-7861bbd5a660_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_9356586b-c855-46c6-a2a9-7861bbd5a660" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_9356586b-c855-46c6-a2a9-7861bbd5a660_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_afe8d43a-89dc-4c7f-bc7b-ab82ab0a9c51" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_9356586b-c855-46c6-a2a9-7861bbd5a660" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_afe8d43a-89dc-4c7f-bc7b-ab82ab0a9c51" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_OryxMidstreamHoldingsLLCMember_214c1a83-4321-4584-b648-e79987ec3062" xlink:href="paa-20211231.xsd#paa_OryxMidstreamHoldingsLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_afe8d43a-89dc-4c7f-bc7b-ab82ab0a9c51" xlink:to="loc_paa_OryxMidstreamHoldingsLLCMember_214c1a83-4321-4584-b648-e79987ec3062" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_DelekLogisticsPartnersLPMember_ad2248d8-ac62-4f46-bf9d-51b3a526e042" xlink:href="paa-20211231.xsd#paa_DelekLogisticsPartnersLPMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_afe8d43a-89dc-4c7f-bc7b-ab82ab0a9c51" xlink:to="loc_paa_DelekLogisticsPartnersLPMember_ad2248d8-ac62-4f46-bf9d-51b3a526e042" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransactionTypeAxis_a6bf1616-a429-4a46-94b2-0928e8de1d51" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransactionTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_paa_PartnersCapitalAndDistributionsTable_164d482d-e036-4e85-9ec0-94eb3be20d9e" xlink:to="loc_us-gaap_TransactionTypeAxis_a6bf1616-a429-4a46-94b2-0928e8de1d51" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransactionDomain_a6bf1616-a429-4a46-94b2-0928e8de1d51_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TransactionTypeAxis_a6bf1616-a429-4a46-94b2-0928e8de1d51" xlink:to="loc_us-gaap_TransactionDomain_a6bf1616-a429-4a46-94b2-0928e8de1d51_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransactionDomain_9f593902-2263-4a82-9307-6d221fa47614" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TransactionTypeAxis_a6bf1616-a429-4a46-94b2-0928e8de1d51" xlink:to="loc_us-gaap_TransactionDomain_9f593902-2263-4a82-9307-6d221fa47614" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_JointVentureFormationMember_910cc013-fd61-414f-996f-24416ef68b5f" xlink:href="paa-20211231.xsd#paa_JointVentureFormationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransactionDomain_9f593902-2263-4a82-9307-6d221fa47614" xlink:to="loc_paa_JointVentureFormationMember_910cc013-fd61-414f-996f-24416ef68b5f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerCapitalComponentsAxis_bc34a85c-e5fd-4fd9-b8bf-fc3a31199a93" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnerCapitalComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_paa_PartnersCapitalAndDistributionsTable_164d482d-e036-4e85-9ec0-94eb3be20d9e" xlink:to="loc_us-gaap_PartnerCapitalComponentsAxis_bc34a85c-e5fd-4fd9-b8bf-fc3a31199a93" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerCapitalComponentsDomain_bc34a85c-e5fd-4fd9-b8bf-fc3a31199a93_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnerCapitalComponentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PartnerCapitalComponentsAxis_bc34a85c-e5fd-4fd9-b8bf-fc3a31199a93" xlink:to="loc_us-gaap_PartnerCapitalComponentsDomain_bc34a85c-e5fd-4fd9-b8bf-fc3a31199a93_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerCapitalComponentsDomain_0242e64a-5211-4190-b0f8-65aba3c36a5a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnerCapitalComponentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PartnerCapitalComponentsAxis_bc34a85c-e5fd-4fd9-b8bf-fc3a31199a93" xlink:to="loc_us-gaap_PartnerCapitalComponentsDomain_0242e64a-5211-4190-b0f8-65aba3c36a5a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncontrollingInterestMember_df440c0c-b584-4134-9244-9f18a853af34" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NoncontrollingInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnerCapitalComponentsDomain_0242e64a-5211-4190-b0f8-65aba3c36a5a" xlink:to="loc_us-gaap_NoncontrollingInterestMember_df440c0c-b584-4134-9244-9f18a853af34" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_e862210e-9414-4b6b-ba2a-6b1ef477a35e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_paa_PartnersCapitalAndDistributionsTable_164d482d-e036-4e85-9ec0-94eb3be20d9e" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_e862210e-9414-4b6b-ba2a-6b1ef477a35e" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_e862210e-9414-4b6b-ba2a-6b1ef477a35e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_e862210e-9414-4b6b-ba2a-6b1ef477a35e" xlink:to="loc_us-gaap_EquityComponentDomain_e862210e-9414-4b6b-ba2a-6b1ef477a35e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_40bde911-56d1-4622-ad0a-ea4e06767956" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_e862210e-9414-4b6b-ba2a-6b1ef477a35e" xlink:to="loc_us-gaap_EquityComponentDomain_40bde911-56d1-4622-ad0a-ea4e06767956" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncontrollingInterestMember_12f1f89a-f29e-49bf-a536-2660f19fab67" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NoncontrollingInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_40bde911-56d1-4622-ad0a-ea4e06767956" xlink:to="loc_us-gaap_NoncontrollingInterestMember_12f1f89a-f29e-49bf-a536-2660f19fab67" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_0616d1aa-3f5f-411a-b7d0-b15866fe994f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_paa_PartnersCapitalAndDistributionsTable_164d482d-e036-4e85-9ec0-94eb3be20d9e" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_0616d1aa-3f5f-411a-b7d0-b15866fe994f" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_0616d1aa-3f5f-411a-b7d0-b15866fe994f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_0616d1aa-3f5f-411a-b7d0-b15866fe994f" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_0616d1aa-3f5f-411a-b7d0-b15866fe994f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_521eb233-c29d-4ea6-9d3e-77e5362092a1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_0616d1aa-3f5f-411a-b7d0-b15866fe994f" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_521eb233-c29d-4ea6-9d3e-77e5362092a1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_e1137a99-532d-433f-86f7-a5fbe0bec2c7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_521eb233-c29d-4ea6-9d3e-77e5362092a1" xlink:to="loc_us-gaap_SubsequentEventMember_e1137a99-532d-433f-86f7-a5fbe0bec2c7" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/DerivativesandRiskManagementActivitiesTables" xlink:type="simple" xlink:href="paa-20211231.xsd#DerivativesandRiskManagementActivitiesTables"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/DerivativesandRiskManagementActivitiesTables" xlink:type="extended" id="ia2ae8693c4fd432a88bf6c0ead2b9b35_DerivativesandRiskManagementActivitiesTables">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLineItems_3334e1e1-9174-43f0-9141-0f4ce9504e06" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfNotionalAmountsOfOutstandingDerivativePositionsTableTextBlock_52f5fe1b-ecb1-486c-9588-793638fd637e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfNotionalAmountsOfOutstandingDerivativePositionsTableTextBlock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_3334e1e1-9174-43f0-9141-0f4ce9504e06" xlink:to="loc_us-gaap_ScheduleOfNotionalAmountsOfOutstandingDerivativePositionsTableTextBlock_52f5fe1b-ecb1-486c-9588-793638fd637e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDerivativeInstrumentsGainLossInStatementOfFinancialPerformanceTextBlock_2f9c2fb9-0800-4eb1-8004-717baa19883e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfDerivativeInstrumentsGainLossInStatementOfFinancialPerformanceTextBlock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_3334e1e1-9174-43f0-9141-0f4ce9504e06" xlink:to="loc_us-gaap_ScheduleOfDerivativeInstrumentsGainLossInStatementOfFinancialPerformanceTextBlock_2f9c2fb9-0800-4eb1-8004-717baa19883e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDueToFromBrokerDealersAndClearingOrganizationsTextBlock_64e992b1-abc3-4fa3-8259-5b4819248248" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfDueToFromBrokerDealersAndClearingOrganizationsTextBlock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_3334e1e1-9174-43f0-9141-0f4ce9504e06" xlink:to="loc_us-gaap_ScheduleOfDueToFromBrokerDealersAndClearingOrganizationsTextBlock_64e992b1-abc3-4fa3-8259-5b4819248248" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDerivativeInstrumentsInStatementOfFinancialPositionFairValueTextBlock_3c04f54a-7843-4507-8f1d-2a7e586b3ac1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfDerivativeInstrumentsInStatementOfFinancialPositionFairValueTextBlock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_3334e1e1-9174-43f0-9141-0f4ce9504e06" xlink:to="loc_us-gaap_ScheduleOfDerivativeInstrumentsInStatementOfFinancialPositionFairValueTextBlock_3c04f54a-7843-4507-8f1d-2a7e586b3ac1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDerivativeInstrumentsTextBlock_5a0df6e3-adfd-4a41-908d-18cb683e0514" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfDerivativeInstrumentsTextBlock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_3334e1e1-9174-43f0-9141-0f4ce9504e06" xlink:to="loc_us-gaap_ScheduleOfDerivativeInstrumentsTextBlock_5a0df6e3-adfd-4a41-908d-18cb683e0514" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfCashFlowHedgesIncludedInAccumulatedOtherComprehensiveIncomeLossTableTextBlock_92e02359-bba6-4d0b-918b-1d904a7cd346" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfCashFlowHedgesIncludedInAccumulatedOtherComprehensiveIncomeLossTableTextBlock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_3334e1e1-9174-43f0-9141-0f4ce9504e06" xlink:to="loc_us-gaap_ScheduleOfCashFlowHedgesIncludedInAccumulatedOtherComprehensiveIncomeLossTableTextBlock_92e02359-bba6-4d0b-918b-1d904a7cd346" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTableTextBlock_4223a2ff-226f-4044-a18a-9dcebdbad82a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfFairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTableTextBlock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_3334e1e1-9174-43f0-9141-0f4ce9504e06" xlink:to="loc_us-gaap_ScheduleOfFairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTableTextBlock_4223a2ff-226f-4044-a18a-9dcebdbad82a" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationTableTextBlock_42e0163f-2fc0-4765-ac7f-22b219516620" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationTableTextBlock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_3334e1e1-9174-43f0-9141-0f4ce9504e06" xlink:to="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationTableTextBlock_42e0163f-2fc0-4765-ac7f-22b219516620" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTable_2644b18e-f6b7-4b89-af4b-a9b08c278b8f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_3334e1e1-9174-43f0-9141-0f4ce9504e06" xlink:to="loc_us-gaap_DerivativeTable_2644b18e-f6b7-4b89-af4b-a9b08c278b8f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_168da1aa-331c-4878-8728-d2ed53d78efc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_2644b18e-f6b7-4b89-af4b-a9b08c278b8f" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_168da1aa-331c-4878-8728-d2ed53d78efc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_168da1aa-331c-4878-8728-d2ed53d78efc_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_168da1aa-331c-4878-8728-d2ed53d78efc" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_168da1aa-331c-4878-8728-d2ed53d78efc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_817595b7-0a66-43b6-b22c-c09f13cad9ea" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_168da1aa-331c-4878-8728-d2ed53d78efc" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_817595b7-0a66-43b6-b22c-c09f13cad9ea" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommodityContractMember_36caa88c-b28b-4925-a2b4-4fc9337cc262" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommodityContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_817595b7-0a66-43b6-b22c-c09f13cad9ea" xlink:to="loc_us-gaap_CommodityContractMember_36caa88c-b28b-4925-a2b4-4fc9337cc262" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateContractMember_d514d373-7d48-4ad4-9457-24a0aa1d9c84" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestRateContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_817595b7-0a66-43b6-b22c-c09f13cad9ea" xlink:to="loc_us-gaap_InterestRateContractMember_d514d373-7d48-4ad4-9457-24a0aa1d9c84" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/DerivativesandRiskManagementActivitiesCommodityPriceRiskHedgingDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#DerivativesandRiskManagementActivitiesCommodityPriceRiskHedgingDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/DerivativesandRiskManagementActivitiesCommodityPriceRiskHedgingDetails" xlink:type="extended" id="i938830826b1348c58792082b78d182cf_DerivativesandRiskManagementActivitiesCommodityPriceRiskHedgingDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLineItems_1ae69cc9-0152-45a9-a47b-f1c61b90b0a1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PriceRiskDerivativesAbstract_2ab9e8f5-32fe-4103-8fd4-e642d2f3d848" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PriceRiskDerivativesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_1ae69cc9-0152-45a9-a47b-f1c61b90b0a1" xlink:to="loc_us-gaap_PriceRiskDerivativesAbstract_2ab9e8f5-32fe-4103-8fd4-e642d2f3d848" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeNonmonetaryNotionalAmountVolume_dc0f5d25-e8d6-4b51-87a3-5d602cbe57a4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeNonmonetaryNotionalAmountVolume"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PriceRiskDerivativesAbstract_2ab9e8f5-32fe-4103-8fd4-e642d2f3d848" xlink:to="loc_us-gaap_DerivativeNonmonetaryNotionalAmountVolume_dc0f5d25-e8d6-4b51-87a3-5d602cbe57a4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeNonmonetaryNotionalAmountEnergyMeasure_1a695ba0-0753-4143-b2ce-6cefa213d48b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeNonmonetaryNotionalAmountEnergyMeasure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PriceRiskDerivativesAbstract_2ab9e8f5-32fe-4103-8fd4-e642d2f3d848" xlink:to="loc_us-gaap_DerivativeNonmonetaryNotionalAmountEnergyMeasure_1a695ba0-0753-4143-b2ce-6cefa213d48b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTable_46affb8e-b8b3-4a4f-b939-e0395ac5eae1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_1ae69cc9-0152-45a9-a47b-f1c61b90b0a1" xlink:to="loc_us-gaap_DerivativeTable_46affb8e-b8b3-4a4f-b939-e0395ac5eae1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_cbe1434e-2f8e-4ee7-8e5c-aef483e9a381" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_46affb8e-b8b3-4a4f-b939-e0395ac5eae1" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_cbe1434e-2f8e-4ee7-8e5c-aef483e9a381" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_cbe1434e-2f8e-4ee7-8e5c-aef483e9a381_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_cbe1434e-2f8e-4ee7-8e5c-aef483e9a381" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_cbe1434e-2f8e-4ee7-8e5c-aef483e9a381_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_dc0c3518-cd2b-47cc-a5e3-7154430fa47c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_cbe1434e-2f8e-4ee7-8e5c-aef483e9a381" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_dc0c3518-cd2b-47cc-a5e3-7154430fa47c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommodityContractMember_598c506c-1351-4232-8da8-3dc137863e3e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommodityContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_dc0c3518-cd2b-47cc-a5e3-7154430fa47c" xlink:to="loc_us-gaap_CommodityContractMember_598c506c-1351-4232-8da8-3dc137863e3e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_CrudeOilDerivativeContractsMember_47dde036-e5d3-4113-a96f-7d401f152db8" xlink:href="paa-20211231.xsd#paa_CrudeOilDerivativeContractsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CommodityContractMember_598c506c-1351-4232-8da8-3dc137863e3e" xlink:to="loc_paa_CrudeOilDerivativeContractsMember_47dde036-e5d3-4113-a96f-7d401f152db8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_TimeSpreadOnHedgeAnticipatedCrudeOilLeaseGatheringPurchaseContractsMember_97d01a0c-8107-4346-bf20-e316cf54bc93" xlink:href="paa-20211231.xsd#paa_TimeSpreadOnHedgeAnticipatedCrudeOilLeaseGatheringPurchaseContractsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CommodityContractMember_598c506c-1351-4232-8da8-3dc137863e3e" xlink:to="loc_paa_TimeSpreadOnHedgeAnticipatedCrudeOilLeaseGatheringPurchaseContractsMember_97d01a0c-8107-4346-bf20-e316cf54bc93" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_CrudeOilGradeBasisPositionMember_066f6b5f-d9af-4835-914b-5c8d3beb16dd" xlink:href="paa-20211231.xsd#paa_CrudeOilGradeBasisPositionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CommodityContractMember_598c506c-1351-4232-8da8-3dc137863e3e" xlink:to="loc_paa_CrudeOilGradeBasisPositionMember_066f6b5f-d9af-4835-914b-5c8d3beb16dd" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_AnticipatedNetSalesOfInventoryMember_f8d153ed-93d1-4d92-98ad-f4d1455a0d71" xlink:href="paa-20211231.xsd#paa_AnticipatedNetSalesOfInventoryMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CommodityContractMember_598c506c-1351-4232-8da8-3dc137863e3e" xlink:to="loc_paa_AnticipatedNetSalesOfInventoryMember_f8d153ed-93d1-4d92-98ad-f4d1455a0d71" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_NaturalGasContractsMember_d1d648f6-1ddb-49d6-9857-12504effd6c0" xlink:href="paa-20211231.xsd#paa_NaturalGasContractsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CommodityContractMember_598c506c-1351-4232-8da8-3dc137863e3e" xlink:to="loc_paa_NaturalGasContractsMember_d1d648f6-1ddb-49d6-9857-12504effd6c0" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PropaneContractsRelatedToSubsequentSaleOfProductMember_5ef12069-2cc7-4a79-b6eb-a406305df097" xlink:href="paa-20211231.xsd#paa_PropaneContractsRelatedToSubsequentSaleOfProductMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CommodityContractMember_598c506c-1351-4232-8da8-3dc137863e3e" xlink:to="loc_paa_PropaneContractsRelatedToSubsequentSaleOfProductMember_5ef12069-2cc7-4a79-b6eb-a406305df097" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_ButaneContractsRelatedToSubsequentSaleOfProductMember_937651cf-a48a-4981-ab56-cfeb0ff122ab" xlink:href="paa-20211231.xsd#paa_ButaneContractsRelatedToSubsequentSaleOfProductMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CommodityContractMember_598c506c-1351-4232-8da8-3dc137863e3e" xlink:to="loc_paa_ButaneContractsRelatedToSubsequentSaleOfProductMember_937651cf-a48a-4981-ab56-cfeb0ff122ab" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_CondensateContractsRelatedToSubsequentSaleOfProductMember_13d9feba-e6fa-4989-9323-27c47428686e" xlink:href="paa-20211231.xsd#paa_CondensateContractsRelatedToSubsequentSaleOfProductMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CommodityContractMember_598c506c-1351-4232-8da8-3dc137863e3e" xlink:to="loc_paa_CondensateContractsRelatedToSubsequentSaleOfProductMember_13d9feba-e6fa-4989-9323-27c47428686e" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_FuelGasRequirementsContractsMember_30aef8db-c79b-483b-a2f7-6adc8ff458fe" xlink:href="paa-20211231.xsd#paa_FuelGasRequirementsContractsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CommodityContractMember_598c506c-1351-4232-8da8-3dc137863e3e" xlink:to="loc_paa_FuelGasRequirementsContractsMember_30aef8db-c79b-483b-a2f7-6adc8ff458fe" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PowerSupplyRequirementsContractsMember_632a7582-e332-427f-ad2c-1ec1db44446d" xlink:href="paa-20211231.xsd#paa_PowerSupplyRequirementsContractsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CommodityContractMember_598c506c-1351-4232-8da8-3dc137863e3e" xlink:to="loc_paa_PowerSupplyRequirementsContractsMember_632a7582-e332-427f-ad2c-1ec1db44446d" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PositionAxis_fa871a94-4c19-4a3a-a407-2a00a3c4d660" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PositionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_46affb8e-b8b3-4a4f-b939-e0395ac5eae1" xlink:to="loc_us-gaap_PositionAxis_fa871a94-4c19-4a3a-a407-2a00a3c4d660" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PositionDomain_fa871a94-4c19-4a3a-a407-2a00a3c4d660_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PositionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PositionAxis_fa871a94-4c19-4a3a-a407-2a00a3c4d660" xlink:to="loc_us-gaap_PositionDomain_fa871a94-4c19-4a3a-a407-2a00a3c4d660_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PositionDomain_50356851-1d3b-42bf-8b16-1255dca2aac7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PositionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PositionAxis_fa871a94-4c19-4a3a-a407-2a00a3c4d660" xlink:to="loc_us-gaap_PositionDomain_50356851-1d3b-42bf-8b16-1255dca2aac7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongMember_74bb685c-c04f-42b3-9292-7f6bbdb7d5f1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PositionDomain_50356851-1d3b-42bf-8b16-1255dca2aac7" xlink:to="loc_us-gaap_LongMember_74bb685c-c04f-42b3-9292-7f6bbdb7d5f1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortMember_ba733f7c-1b3c-4dde-ba9f-13e06a20cce6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PositionDomain_50356851-1d3b-42bf-8b16-1255dca2aac7" xlink:to="loc_us-gaap_ShortMember_ba733f7c-1b3c-4dde-ba9f-13e06a20cce6" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/DerivativesandRiskManagementActivitiesFinancialImpactDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#DerivativesandRiskManagementActivitiesFinancialImpactDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/DerivativesandRiskManagementActivitiesFinancialImpactDetails" xlink:type="extended" id="iacc58051fe8f4966979fb71dbf096e13_DerivativesandRiskManagementActivitiesFinancialImpactDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_06bf28bd-339f-4a57-96d0-203aa58c761e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeGainLossOnDerivativeNet_1cc0d617-6c1e-4ace-abd1-22d09e3920e9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeGainLossOnDerivativeNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_06bf28bd-339f-4a57-96d0-203aa58c761e" xlink:to="loc_us-gaap_DerivativeGainLossOnDerivativeNet_1cc0d617-6c1e-4ace-abd1-22d09e3920e9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_e19119b6-daec-47a5-88bf-8d04114a620b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_06bf28bd-339f-4a57-96d0-203aa58c761e" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_e19119b6-daec-47a5-88bf-8d04114a620b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_53ec7fbc-dabb-4a78-a5b0-de6e0423734c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_e19119b6-daec-47a5-88bf-8d04114a620b" xlink:to="loc_us-gaap_HedgingDesignationAxis_53ec7fbc-dabb-4a78-a5b0-de6e0423734c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_53ec7fbc-dabb-4a78-a5b0-de6e0423734c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_53ec7fbc-dabb-4a78-a5b0-de6e0423734c" xlink:to="loc_us-gaap_HedgingDesignationDomain_53ec7fbc-dabb-4a78-a5b0-de6e0423734c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_ebd76f8b-2335-4dc3-9357-caee6e480ebf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_53ec7fbc-dabb-4a78-a5b0-de6e0423734c" xlink:to="loc_us-gaap_HedgingDesignationDomain_ebd76f8b-2335-4dc3-9357-caee6e480ebf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NondesignatedMember_b0aca384-24b5-4517-937e-cfd35383c124" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NondesignatedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_ebd76f8b-2335-4dc3-9357-caee6e480ebf" xlink:to="loc_us-gaap_NondesignatedMember_b0aca384-24b5-4517-937e-cfd35383c124" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_ae31ce4f-e9e6-4a7a-b4de-e88645f78114" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_e19119b6-daec-47a5-88bf-8d04114a620b" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_ae31ce4f-e9e6-4a7a-b4de-e88645f78114" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_ae31ce4f-e9e6-4a7a-b4de-e88645f78114_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_ae31ce4f-e9e6-4a7a-b4de-e88645f78114" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_ae31ce4f-e9e6-4a7a-b4de-e88645f78114_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_fe2c9f0d-14a2-461f-a0d1-80a52798a53a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_ae31ce4f-e9e6-4a7a-b4de-e88645f78114" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_fe2c9f0d-14a2-461f-a0d1-80a52798a53a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommodityContractMember_636248e5-4757-488f-a3f0-f396f4bef0f3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommodityContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_fe2c9f0d-14a2-461f-a0d1-80a52798a53a" xlink:to="loc_us-gaap_CommodityContractMember_636248e5-4757-488f-a3f0-f396f4bef0f3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_f7e4975e-caf3-4206-9bad-c235b92897a0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_e19119b6-daec-47a5-88bf-8d04114a620b" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_f7e4975e-caf3-4206-9bad-c235b92897a0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_f7e4975e-caf3-4206-9bad-c235b92897a0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_f7e4975e-caf3-4206-9bad-c235b92897a0" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_f7e4975e-caf3-4206-9bad-c235b92897a0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_97c5a53f-f2b4-415b-8dc2-97406bac735f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_f7e4975e-caf3-4206-9bad-c235b92897a0" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_97c5a53f-f2b4-415b-8dc2-97406bac735f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProductMember_ff0a0e70-75c6-4c5b-9534-fa791d281d30" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProductMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_97c5a53f-f2b4-415b-8dc2-97406bac735f" xlink:to="loc_us-gaap_ProductMember_ff0a0e70-75c6-4c5b-9534-fa791d281d30" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_FieldOperatingCostsMember_77948671-c06e-4220-9109-f34c5627272a" xlink:href="paa-20211231.xsd#paa_FieldOperatingCostsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_97c5a53f-f2b4-415b-8dc2-97406bac735f" xlink:to="loc_paa_FieldOperatingCostsMember_77948671-c06e-4220-9109-f34c5627272a" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/DerivativesandRiskManagementActivitiesAssetsandLiabilitiesDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#DerivativesandRiskManagementActivitiesAssetsandLiabilitiesDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/DerivativesandRiskManagementActivitiesAssetsandLiabilitiesDetails" xlink:type="extended" id="i45a02ad08d33448eb06a7e91606bc36d_DerivativesandRiskManagementActivitiesAssetsandLiabilitiesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativesFairValueLineItems_3413deb0-feed-4da7-bd02-91ca26f89a93" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativesFairValueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_InitialMargin_5157ab0f-5c99-4c62-b194-e1ce24b4bcb4" xlink:href="paa-20211231.xsd#paa_InitialMargin"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_3413deb0-feed-4da7-bd02-91ca26f89a93" xlink:to="loc_paa_InitialMargin_5157ab0f-5c99-4c62-b194-e1ce24b4bcb4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_VariationMarginPostedReturned_df8ce63e-32c8-4008-8cd7-78a6ed6dc800" xlink:href="paa-20211231.xsd#paa_VariationMarginPostedReturned"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_3413deb0-feed-4da7-bd02-91ca26f89a93" xlink:to="loc_paa_VariationMarginPostedReturned_df8ce63e-32c8-4008-8cd7-78a6ed6dc800" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LettersOfCreditOutstandingAmount_b470bcf4-6623-46a7-b811-f399336fa14c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LettersOfCreditOutstandingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_3413deb0-feed-4da7-bd02-91ca26f89a93" xlink:to="loc_us-gaap_LettersOfCreditOutstandingAmount_b470bcf4-6623-46a7-b811-f399336fa14c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilityCollateralRightToReclaimCashOffset_f216f25e-fcfb-4d4f-bcb6-b058d5bdf6e8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeLiabilityCollateralRightToReclaimCashOffset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_3413deb0-feed-4da7-bd02-91ca26f89a93" xlink:to="loc_us-gaap_DerivativeLiabilityCollateralRightToReclaimCashOffset_f216f25e-fcfb-4d4f-bcb6-b058d5bdf6e8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_9e945c06-6373-4f80-8f50-9b8d01329706" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_3413deb0-feed-4da7-bd02-91ca26f89a93" xlink:to="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_9e945c06-6373-4f80-8f50-9b8d01329706" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransactionTypeAxis_1433d2e2-eb43-4b35-bd59-d381049afd05" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransactionTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_9e945c06-6373-4f80-8f50-9b8d01329706" xlink:to="loc_us-gaap_TransactionTypeAxis_1433d2e2-eb43-4b35-bd59-d381049afd05" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransactionDomain_1433d2e2-eb43-4b35-bd59-d381049afd05_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TransactionTypeAxis_1433d2e2-eb43-4b35-bd59-d381049afd05" xlink:to="loc_us-gaap_TransactionDomain_1433d2e2-eb43-4b35-bd59-d381049afd05_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransactionDomain_dac49092-bffa-4469-8511-4619f4f20446" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TransactionTypeAxis_1433d2e2-eb43-4b35-bd59-d381049afd05" xlink:to="loc_us-gaap_TransactionDomain_dac49092-bffa-4469-8511-4619f4f20446" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ExchangeTradedMember_bc93b72c-b5ff-42e3-8dd3-94866aba5c0f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ExchangeTradedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransactionDomain_dac49092-bffa-4469-8511-4619f4f20446" xlink:to="loc_us-gaap_ExchangeTradedMember_bc93b72c-b5ff-42e3-8dd3-94866aba5c0f" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/DerivativesandRiskManagementActivitiesOffsettingDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#DerivativesandRiskManagementActivitiesOffsettingDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/DerivativesandRiskManagementActivitiesOffsettingDetails" xlink:type="extended" id="iaa36fe8a084e48e7a4f404c422992643_DerivativesandRiskManagementActivitiesOffsettingDetails">
    <link:loc xlink:type="locator" xlink:label="loc_paa_OffsettingAssetsLiabilitiesLineItems_eaf62d33-2722-44f7-8462-972efda25045" xlink:href="paa-20211231.xsd#paa_OffsettingAssetsLiabilitiesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OffsettingAbstract_c4924b9c-416c-4f70-8bd3-8918d8fdb217" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OffsettingAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_paa_OffsettingAssetsLiabilitiesLineItems_eaf62d33-2722-44f7-8462-972efda25045" xlink:to="loc_us-gaap_OffsettingAbstract_c4924b9c-416c-4f70-8bd3-8918d8fdb217" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OffsettingDerivativeAssetsAbstract_a3accfa1-3e0d-45df-ae58-b2418bee127e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OffsettingDerivativeAssetsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OffsettingAbstract_c4924b9c-416c-4f70-8bd3-8918d8fdb217" xlink:to="loc_us-gaap_OffsettingDerivativeAssetsAbstract_a3accfa1-3e0d-45df-ae58-b2418bee127e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeAsset_5cfa67bb-1e1e-4aff-988c-a21868e45889" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeFairValueOfDerivativeAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OffsettingDerivativeAssetsAbstract_a3accfa1-3e0d-45df-ae58-b2418bee127e" xlink:to="loc_us-gaap_DerivativeFairValueOfDerivativeAsset_5cfa67bb-1e1e-4aff-988c-a21868e45889" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssetFairValueGrossLiability_fe855406-28a0-41e8-a393-4a53f5cb92f0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeAssetFairValueGrossLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OffsettingDerivativeAssetsAbstract_a3accfa1-3e0d-45df-ae58-b2418bee127e" xlink:to="loc_us-gaap_DerivativeAssetFairValueGrossLiability_fe855406-28a0-41e8-a393-4a53f5cb92f0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilityCollateralRightToReclaimCashOffset_ca2fd1df-682a-47d0-9117-13580537e054" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeLiabilityCollateralRightToReclaimCashOffset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OffsettingDerivativeAssetsAbstract_a3accfa1-3e0d-45df-ae58-b2418bee127e" xlink:to="loc_us-gaap_DerivativeLiabilityCollateralRightToReclaimCashOffset_ca2fd1df-682a-47d0-9117-13580537e054" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssets_25c314df-dfad-4bd1-b352-aaf6db79354e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OffsettingDerivativeAssetsAbstract_a3accfa1-3e0d-45df-ae58-b2418bee127e" xlink:to="loc_us-gaap_DerivativeAssets_25c314df-dfad-4bd1-b352-aaf6db79354e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OffsettingDerivativeLiabilitiesAbstract_ff277152-a131-475c-b939-1c1b062350ce" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OffsettingDerivativeLiabilitiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OffsettingAbstract_c4924b9c-416c-4f70-8bd3-8918d8fdb217" xlink:to="loc_us-gaap_OffsettingDerivativeLiabilitiesAbstract_ff277152-a131-475c-b939-1c1b062350ce" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilityFairValueGrossAsset_17705653-0596-4f5c-90c4-84f8c01b98fe" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeLiabilityFairValueGrossAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OffsettingDerivativeLiabilitiesAbstract_ff277152-a131-475c-b939-1c1b062350ce" xlink:to="loc_us-gaap_DerivativeLiabilityFairValueGrossAsset_17705653-0596-4f5c-90c4-84f8c01b98fe" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeLiability_5338b433-b8b6-44cc-9940-f811ffcc166a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeFairValueOfDerivativeLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OffsettingDerivativeLiabilitiesAbstract_ff277152-a131-475c-b939-1c1b062350ce" xlink:to="loc_us-gaap_DerivativeFairValueOfDerivativeLiability_5338b433-b8b6-44cc-9940-f811ffcc166a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilities_bfaba17f-d3be-4b5a-a613-b8d6581687e1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OffsettingDerivativeLiabilitiesAbstract_ff277152-a131-475c-b939-1c1b062350ce" xlink:to="loc_us-gaap_DerivativeLiabilities_bfaba17f-d3be-4b5a-a613-b8d6581687e1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssetsLiabilitiesAtFairValueNet_cc8a170c-4ef0-4ee3-9ccf-7c3c916f765b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeAssetsLiabilitiesAtFairValueNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OffsettingAbstract_c4924b9c-416c-4f70-8bd3-8918d8fdb217" xlink:to="loc_us-gaap_DerivativeAssetsLiabilitiesAtFairValueNet_cc8a170c-4ef0-4ee3-9ccf-7c3c916f765b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_OffsettingAssetsLiabilitiesTable_9abf7a7a-f554-4baa-855e-eecea3190a9b" xlink:href="paa-20211231.xsd#paa_OffsettingAssetsLiabilitiesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_paa_OffsettingAssetsLiabilitiesLineItems_eaf62d33-2722-44f7-8462-972efda25045" xlink:to="loc_paa_OffsettingAssetsLiabilitiesTable_9abf7a7a-f554-4baa-855e-eecea3190a9b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_c564c519-2382-400f-a0fd-fc4810e59330" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_paa_OffsettingAssetsLiabilitiesTable_9abf7a7a-f554-4baa-855e-eecea3190a9b" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_c564c519-2382-400f-a0fd-fc4810e59330" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_c564c519-2382-400f-a0fd-fc4810e59330_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_c564c519-2382-400f-a0fd-fc4810e59330" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_c564c519-2382-400f-a0fd-fc4810e59330_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_9d287080-b9d8-4620-ac96-a61e8e287724" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_c564c519-2382-400f-a0fd-fc4810e59330" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_9d287080-b9d8-4620-ac96-a61e8e287724" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCurrentAssetsMember_27c5d3be-7e2b-4a5c-80f1-ce03679a1bc2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherCurrentAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_9d287080-b9d8-4620-ac96-a61e8e287724" xlink:to="loc_us-gaap_OtherCurrentAssetsMember_27c5d3be-7e2b-4a5c-80f1-ce03679a1bc2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNoncurrentAssetsMember_99151fcd-debd-47f5-9c1a-fe0e3e261fd4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherNoncurrentAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_9d287080-b9d8-4620-ac96-a61e8e287724" xlink:to="loc_us-gaap_OtherNoncurrentAssetsMember_99151fcd-debd-47f5-9c1a-fe0e3e261fd4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCurrentLiabilitiesMember_c04c248e-275e-4531-8190-4436ad3a9e5d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherCurrentLiabilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_9d287080-b9d8-4620-ac96-a61e8e287724" xlink:to="loc_us-gaap_OtherCurrentLiabilitiesMember_c04c248e-275e-4531-8190-4436ad3a9e5d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNoncurrentLiabilitiesMember_b0248c92-c9c6-4eff-a9f6-f9bc340b4de4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherNoncurrentLiabilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_9d287080-b9d8-4620-ac96-a61e8e287724" xlink:to="loc_us-gaap_OtherNoncurrentLiabilitiesMember_b0248c92-c9c6-4eff-a9f6-f9bc340b4de4" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_3491c9c1-dd8f-4852-89f7-ac58692d0354" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_paa_OffsettingAssetsLiabilitiesTable_9abf7a7a-f554-4baa-855e-eecea3190a9b" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_3491c9c1-dd8f-4852-89f7-ac58692d0354" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_3491c9c1-dd8f-4852-89f7-ac58692d0354_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_3491c9c1-dd8f-4852-89f7-ac58692d0354" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_3491c9c1-dd8f-4852-89f7-ac58692d0354_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_c4e7eab9-ce53-42cf-9530-33f9636078f6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_3491c9c1-dd8f-4852-89f7-ac58692d0354" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_c4e7eab9-ce53-42cf-9530-33f9636078f6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommodityContractMember_3f4f9fef-6c2f-43c7-b4a9-6032e55cec17" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommodityContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_c4e7eab9-ce53-42cf-9530-33f9636078f6" xlink:to="loc_us-gaap_CommodityContractMember_3f4f9fef-6c2f-43c7-b4a9-6032e55cec17" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/DerivativesandRiskManagementActivitiesInterestRateRiskHedgingDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#DerivativesandRiskManagementActivitiesInterestRateRiskHedgingDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/DerivativesandRiskManagementActivitiesInterestRateRiskHedgingDetails" xlink:type="extended" id="ie3430f8d40f5476c8f4cdf5c2589e684_DerivativesandRiskManagementActivitiesInterestRateRiskHedgingDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLineItems_ef7b2ace-e14d-4143-86e3-601b337d2e31" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateDerivativesAbstract_ae926fb4-b2b6-4edb-9876-1991f9b163bc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestRateDerivativesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_ef7b2ace-e14d-4143-86e3-601b337d2e31" xlink:to="loc_us-gaap_InterestRateDerivativesAbstract_ae926fb4-b2b6-4edb-9876-1991f9b163bc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfInterestRateDerivativesHeld_53aee7c7-f414-4614-b1f7-5d03387d3af3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NumberOfInterestRateDerivativesHeld"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestRateDerivativesAbstract_ae926fb4-b2b6-4edb-9876-1991f9b163bc" xlink:to="loc_us-gaap_NumberOfInterestRateDerivativesHeld_53aee7c7-f414-4614-b1f7-5d03387d3af3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTermOfContract_fd4fd68e-32ec-49ab-bc01-2f078f8276d0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeTermOfContract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestRateDerivativesAbstract_ae926fb4-b2b6-4edb-9876-1991f9b163bc" xlink:to="loc_us-gaap_DerivativeTermOfContract_fd4fd68e-32ec-49ab-bc01-2f078f8276d0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeNotionalAmount_ab4eaca2-669b-4641-bd7f-70da2bd3ea5e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeNotionalAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestRateDerivativesAbstract_ae926fb4-b2b6-4edb-9876-1991f9b163bc" xlink:to="loc_us-gaap_DerivativeNotionalAmount_ab4eaca2-669b-4641-bd7f-70da2bd3ea5e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAverageFixedInterestRate_28e3fa84-41fb-4f65-a2a8-acca9df00211" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeAverageFixedInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestRateDerivativesAbstract_ae926fb4-b2b6-4edb-9876-1991f9b163bc" xlink:to="loc_us-gaap_DerivativeAverageFixedInterestRate_28e3fa84-41fb-4f65-a2a8-acca9df00211" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTable_51e120b0-cdec-4e51-88c6-bbed86f8d9f7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_ef7b2ace-e14d-4143-86e3-601b337d2e31" xlink:to="loc_us-gaap_DerivativeTable_51e120b0-cdec-4e51-88c6-bbed86f8d9f7" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_a72eeeac-4017-4a78-8ff8-ed38ef7f77ab" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_51e120b0-cdec-4e51-88c6-bbed86f8d9f7" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_a72eeeac-4017-4a78-8ff8-ed38ef7f77ab" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_a72eeeac-4017-4a78-8ff8-ed38ef7f77ab_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_a72eeeac-4017-4a78-8ff8-ed38ef7f77ab" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_a72eeeac-4017-4a78-8ff8-ed38ef7f77ab_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_cd9e761f-a972-4eef-8544-78f0cefbd2b4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_a72eeeac-4017-4a78-8ff8-ed38ef7f77ab" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_cd9e761f-a972-4eef-8544-78f0cefbd2b4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateContractMember_1a57a0b7-073b-4b55-9f11-d8dd14e23718" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestRateContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_cd9e761f-a972-4eef-8544-78f0cefbd2b4" xlink:to="loc_us-gaap_InterestRateContractMember_1a57a0b7-073b-4b55-9f11-d8dd14e23718" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_EightForwardStartingThirtyYearInterestRateSwaps138PercentMember_8cad16f1-d622-4660-a371-2971dbbf230d" xlink:href="paa-20211231.xsd#paa_EightForwardStartingThirtyYearInterestRateSwaps138PercentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestRateContractMember_1a57a0b7-073b-4b55-9f11-d8dd14e23718" xlink:to="loc_paa_EightForwardStartingThirtyYearInterestRateSwaps138PercentMember_8cad16f1-d622-4660-a371-2971dbbf230d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_EightForwardStartingThirtyYearInterestRateSwaps073PercentMember_a35c1fa6-9f9a-4c8a-a1c6-098418fccade" xlink:href="paa-20211231.xsd#paa_EightForwardStartingThirtyYearInterestRateSwaps073PercentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestRateContractMember_1a57a0b7-073b-4b55-9f11-d8dd14e23718" xlink:to="loc_paa_EightForwardStartingThirtyYearInterestRateSwaps073PercentMember_a35c1fa6-9f9a-4c8a-a1c6-098418fccade" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_86532beb-7801-4966-8c09-360357729706" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_51e120b0-cdec-4e51-88c6-bbed86f8d9f7" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_86532beb-7801-4966-8c09-360357729706" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_86532beb-7801-4966-8c09-360357729706_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_86532beb-7801-4966-8c09-360357729706" xlink:to="loc_us-gaap_HedgingRelationshipDomain_86532beb-7801-4966-8c09-360357729706_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_05a2dd76-f52b-4305-9e9d-fdf813395fb4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_86532beb-7801-4966-8c09-360357729706" xlink:to="loc_us-gaap_HedgingRelationshipDomain_05a2dd76-f52b-4305-9e9d-fdf813395fb4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashFlowHedgingMember_6f7e6a3a-307f-4969-a042-27e7a06cb798" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashFlowHedgingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingRelationshipDomain_05a2dd76-f52b-4305-9e9d-fdf813395fb4" xlink:to="loc_us-gaap_CashFlowHedgingMember_6f7e6a3a-307f-4969-a042-27e7a06cb798" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/DerivativesandRiskManagementActivitiesNetUnrealizedGainLossRecognizedinAOCIDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#DerivativesandRiskManagementActivitiesNetUnrealizedGainLossRecognizedinAOCIDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/DerivativesandRiskManagementActivitiesNetUnrealizedGainLossRecognizedinAOCIDetails" xlink:type="extended" id="icb250fdf18d2499eb0ff5d89f7264904_DerivativesandRiskManagementActivitiesNetUnrealizedGainLossRecognizedinAOCIDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativesFairValueLineItems_dd825292-e2ae-481f-8fea-0660e17c46ef" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativesFairValueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_24b0eff0-bd61-40ec-ac6a-8a65e984fba4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_dd825292-e2ae-481f-8fea-0660e17c46ef" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_24b0eff0-bd61-40ec-ac6a-8a65e984fba4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax_d3bdd1b7-3c0c-4464-a396-a29d39e3d92e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_dd825292-e2ae-481f-8fea-0660e17c46ef" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax_d3bdd1b7-3c0c-4464-a396-a29d39e3d92e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateFairValueHedgeLiabilityAtFairValue_55cf7102-fd75-4d0c-b8db-319bbb29bee7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestRateFairValueHedgeLiabilityAtFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_dd825292-e2ae-481f-8fea-0660e17c46ef" xlink:to="loc_us-gaap_InterestRateFairValueHedgeLiabilityAtFairValue_55cf7102-fd75-4d0c-b8db-319bbb29bee7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_c01effd1-1be0-4331-b16c-b09078d9ef56" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_dd825292-e2ae-481f-8fea-0660e17c46ef" xlink:to="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_c01effd1-1be0-4331-b16c-b09078d9ef56" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_a1935b9a-d848-4b6d-8b0b-83af3ae6e045" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_c01effd1-1be0-4331-b16c-b09078d9ef56" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_a1935b9a-d848-4b6d-8b0b-83af3ae6e045" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_a1935b9a-d848-4b6d-8b0b-83af3ae6e045_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_a1935b9a-d848-4b6d-8b0b-83af3ae6e045" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_a1935b9a-d848-4b6d-8b0b-83af3ae6e045_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_40080e84-95bf-4a85-a1aa-7d248d17f88a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_a1935b9a-d848-4b6d-8b0b-83af3ae6e045" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_40080e84-95bf-4a85-a1aa-7d248d17f88a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateContractMember_7d5949cf-1bb0-4005-8afa-dc3baf98e299" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestRateContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_40080e84-95bf-4a85-a1aa-7d248d17f88a" xlink:to="loc_us-gaap_InterestRateContractMember_7d5949cf-1bb0-4005-8afa-dc3baf98e299" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_ecbd86b4-c473-4625-a18d-bfcc01edb82e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_c01effd1-1be0-4331-b16c-b09078d9ef56" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_ecbd86b4-c473-4625-a18d-bfcc01edb82e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_ecbd86b4-c473-4625-a18d-bfcc01edb82e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_ecbd86b4-c473-4625-a18d-bfcc01edb82e" xlink:to="loc_us-gaap_EquityComponentDomain_ecbd86b4-c473-4625-a18d-bfcc01edb82e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_a3035bb0-4567-4067-aae9-914b0a55c264" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_ecbd86b4-c473-4625-a18d-bfcc01edb82e" xlink:to="loc_us-gaap_EquityComponentDomain_a3035bb0-4567-4067-aae9-914b0a55c264" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedGainLossCashFlowHedgeIncludingNoncontrollingInterestMember_3ffdcede-9686-4d73-926a-78fbdf652f93" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedGainLossCashFlowHedgeIncludingNoncontrollingInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_a3035bb0-4567-4067-aae9-914b0a55c264" xlink:to="loc_us-gaap_AccumulatedGainLossCashFlowHedgeIncludingNoncontrollingInterestMember_3ffdcede-9686-4d73-926a-78fbdf652f93" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_fb81111f-4732-4230-b7e8-b3f4aac98661" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_c01effd1-1be0-4331-b16c-b09078d9ef56" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_fb81111f-4732-4230-b7e8-b3f4aac98661" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_fb81111f-4732-4230-b7e8-b3f4aac98661_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_fb81111f-4732-4230-b7e8-b3f4aac98661" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_fb81111f-4732-4230-b7e8-b3f4aac98661_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_25c39757-0136-49d7-8ba2-39a91edf872a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_fb81111f-4732-4230-b7e8-b3f4aac98661" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_25c39757-0136-49d7-8ba2-39a91edf872a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNoncurrentAssetsMember_8028e098-7f0d-4aeb-b49f-d1bee7ce0199" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherNoncurrentAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_25c39757-0136-49d7-8ba2-39a91edf872a" xlink:to="loc_us-gaap_OtherNoncurrentAssetsMember_8028e098-7f0d-4aeb-b49f-d1bee7ce0199" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/DerivativesandRiskManagementActivitiesPreferredDistributionRateDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#DerivativesandRiskManagementActivitiesPreferredDistributionRateDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/DerivativesandRiskManagementActivitiesPreferredDistributionRateDetails" xlink:type="extended" id="if1991b6e45504715a324594379e05e30_DerivativesandRiskManagementActivitiesPreferredDistributionRateDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLineItems_a187a433-626e-4b24-ba86-b417544602b1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmbeddedDerivativeGainLossOnEmbeddedDerivativeNet_c40d5a4b-eb03-4a60-994e-70724f9c4bc8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EmbeddedDerivativeGainLossOnEmbeddedDerivativeNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_a187a433-626e-4b24-ba86-b417544602b1" xlink:to="loc_us-gaap_EmbeddedDerivativeGainLossOnEmbeddedDerivativeNet_c40d5a4b-eb03-4a60-994e-70724f9c4bc8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilities_1d9e904f-9375-42bb-948a-b473ddebd2ce" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_a187a433-626e-4b24-ba86-b417544602b1" xlink:to="loc_us-gaap_DerivativeLiabilities_1d9e904f-9375-42bb-948a-b473ddebd2ce" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTable_9d424c5f-5b9f-4f8a-87ed-1fdb45915540" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_a187a433-626e-4b24-ba86-b417544602b1" xlink:to="loc_us-gaap_DerivativeTable_9d424c5f-5b9f-4f8a-87ed-1fdb45915540" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_75554877-a536-4937-aefe-a914705bc2b4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_9d424c5f-5b9f-4f8a-87ed-1fdb45915540" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_75554877-a536-4937-aefe-a914705bc2b4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_75554877-a536-4937-aefe-a914705bc2b4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_75554877-a536-4937-aefe-a914705bc2b4" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_75554877-a536-4937-aefe-a914705bc2b4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_55e61300-76c0-42f2-8492-4d0af8793eed" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_75554877-a536-4937-aefe-a914705bc2b4" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_55e61300-76c0-42f2-8492-4d0af8793eed" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmbeddedDerivativeFinancialInstrumentsMember_f9e11359-74b3-440f-8daf-ceb2a2d9ddab" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EmbeddedDerivativeFinancialInstrumentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_55e61300-76c0-42f2-8492-4d0af8793eed" xlink:to="loc_us-gaap_EmbeddedDerivativeFinancialInstrumentsMember_f9e11359-74b3-440f-8daf-ceb2a2d9ddab" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_7ace6591-6570-4d71-934d-62fd8d163b3f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_9d424c5f-5b9f-4f8a-87ed-1fdb45915540" xlink:to="loc_us-gaap_HedgingDesignationAxis_7ace6591-6570-4d71-934d-62fd8d163b3f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_7ace6591-6570-4d71-934d-62fd8d163b3f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_7ace6591-6570-4d71-934d-62fd8d163b3f" xlink:to="loc_us-gaap_HedgingDesignationDomain_7ace6591-6570-4d71-934d-62fd8d163b3f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_bdbce527-c88a-43eb-804a-9fd0031e0461" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_7ace6591-6570-4d71-934d-62fd8d163b3f" xlink:to="loc_us-gaap_HedgingDesignationDomain_bdbce527-c88a-43eb-804a-9fd0031e0461" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NondesignatedMember_7acb83e0-ca32-42e6-8157-c53f793f54d3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NondesignatedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_bdbce527-c88a-43eb-804a-9fd0031e0461" xlink:to="loc_us-gaap_NondesignatedMember_7acb83e0-ca32-42e6-8157-c53f793f54d3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_ab84971c-7311-49ef-94d0-43abc7ca4353" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_9d424c5f-5b9f-4f8a-87ed-1fdb45915540" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_ab84971c-7311-49ef-94d0-43abc7ca4353" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_ab84971c-7311-49ef-94d0-43abc7ca4353_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_ab84971c-7311-49ef-94d0-43abc7ca4353" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_ab84971c-7311-49ef-94d0-43abc7ca4353_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_bcf055be-39de-43ea-9cb7-5c587ff320c9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_ab84971c-7311-49ef-94d0-43abc7ca4353" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_bcf055be-39de-43ea-9cb7-5c587ff320c9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpenseMember_f7f8501b-3766-46eb-9045-129cd2196a06" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherNonoperatingIncomeExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_bcf055be-39de-43ea-9cb7-5c587ff320c9" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpenseMember_f7f8501b-3766-46eb-9045-129cd2196a06" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_2bd87c2c-59df-4840-94da-6967b4d30653" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_9d424c5f-5b9f-4f8a-87ed-1fdb45915540" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_2bd87c2c-59df-4840-94da-6967b4d30653" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_2bd87c2c-59df-4840-94da-6967b4d30653_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_2bd87c2c-59df-4840-94da-6967b4d30653" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_2bd87c2c-59df-4840-94da-6967b4d30653_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_549d61d7-e267-422e-965e-4a1714c7272a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_2bd87c2c-59df-4840-94da-6967b4d30653" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_549d61d7-e267-422e-965e-4a1714c7272a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNoncurrentLiabilitiesMember_7b1fb3e5-9de2-4e3d-8684-6ec88f3e34a3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherNoncurrentLiabilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_549d61d7-e267-422e-965e-4a1714c7272a" xlink:to="loc_us-gaap_OtherNoncurrentLiabilitiesMember_7b1fb3e5-9de2-4e3d-8684-6ec88f3e34a3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_afe09cc2-f7b8-4bee-89fa-1688248cc8dc" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_9d424c5f-5b9f-4f8a-87ed-1fdb45915540" xlink:to="loc_srt_RangeAxis_afe09cc2-f7b8-4bee-89fa-1688248cc8dc" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_afe09cc2-f7b8-4bee-89fa-1688248cc8dc_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_afe09cc2-f7b8-4bee-89fa-1688248cc8dc" xlink:to="loc_srt_RangeMember_afe09cc2-f7b8-4bee-89fa-1688248cc8dc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_8f4237d1-3d43-4cd3-bc24-3dc2a27d1baf" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_afe09cc2-f7b8-4bee-89fa-1688248cc8dc" xlink:to="loc_srt_RangeMember_8f4237d1-3d43-4cd3-bc24-3dc2a27d1baf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_43aea5fe-4a61-4680-83da-21e06960184e" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_8f4237d1-3d43-4cd3-bc24-3dc2a27d1baf" xlink:to="loc_srt_MaximumMember_43aea5fe-4a61-4680-83da-21e06960184e" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/DerivativesandRiskManagementActivitiesFairValueDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#DerivativesandRiskManagementActivitiesFairValueDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/DerivativesandRiskManagementActivitiesFairValueDetails" xlink:type="extended" id="ife61cde9c2ed401b8cf1b4bff86e5fb5_DerivativesandRiskManagementActivitiesFairValueDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_e8cb82b5-b7d6-40dd-865b-88d646d9c899" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeNet_418187e1-8d1c-422e-8052-1bc44c59f948" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeFairValueOfDerivativeNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_e8cb82b5-b7d6-40dd-865b-88d646d9c899" xlink:to="loc_us-gaap_DerivativeFairValueOfDerivativeNet_418187e1-8d1c-422e-8052-1bc44c59f948" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationRollForward_6d0e33ad-8998-49c2-a066-1b3136ecca56" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_e8cb82b5-b7d6-40dd-865b-88d646d9c899" xlink:to="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationRollForward_6d0e33ad-8998-49c2-a066-1b3136ecca56" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs_a0b781ea-e0f2-4b16-89c0-e45df879b02a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationRollForward_6d0e33ad-8998-49c2-a066-1b3136ecca56" xlink:to="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs_a0b781ea-e0f2-4b16-89c0-e45df879b02a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationGainLossIncludedInEarnings_96af1c8e-24f6-4b4c-b78a-76526dac75e1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationGainLossIncludedInEarnings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationRollForward_6d0e33ad-8998-49c2-a066-1b3136ecca56" xlink:to="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationGainLossIncludedInEarnings_96af1c8e-24f6-4b4c-b78a-76526dac75e1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationSettlements_3ddce877-e094-419f-8744-37c00e1af58e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationSettlements"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationRollForward_6d0e33ad-8998-49c2-a066-1b3136ecca56" xlink:to="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationSettlements_3ddce877-e094-419f-8744-37c00e1af58e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs_fe1b1cc1-771d-4567-a9c3-0fc49bcd48fa" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainLoss_107332db-54f6-4dbb-be74-1f3e89605bca" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_e8cb82b5-b7d6-40dd-865b-88d646d9c899" xlink:to="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainLoss_107332db-54f6-4dbb-be74-1f3e89605bca" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_071b5d70-c4ea-480d-bbf2-4a64a950ad52" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_e8cb82b5-b7d6-40dd-865b-88d646d9c899" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_071b5d70-c4ea-480d-bbf2-4a64a950ad52" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_7eb52531-6190-4679-b1cc-e98ee552432a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_071b5d70-c4ea-480d-bbf2-4a64a950ad52" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_7eb52531-6190-4679-b1cc-e98ee552432a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_7eb52531-6190-4679-b1cc-e98ee552432a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_7eb52531-6190-4679-b1cc-e98ee552432a" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_7eb52531-6190-4679-b1cc-e98ee552432a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_6e0abb28-cc43-45b7-ab55-e3e90b05992c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_7eb52531-6190-4679-b1cc-e98ee552432a" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_6e0abb28-cc43-45b7-ab55-e3e90b05992c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_0d72bfd2-0e2e-4b8c-8ecb-1bc07d975331" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsRecurringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_6e0abb28-cc43-45b7-ab55-e3e90b05992c" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_0d72bfd2-0e2e-4b8c-8ecb-1bc07d975331" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_5534e237-ecea-4f5c-a9fb-8d611cccf378" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_071b5d70-c4ea-480d-bbf2-4a64a950ad52" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_5534e237-ecea-4f5c-a9fb-8d611cccf378" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_5534e237-ecea-4f5c-a9fb-8d611cccf378_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_5534e237-ecea-4f5c-a9fb-8d611cccf378" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_5534e237-ecea-4f5c-a9fb-8d611cccf378_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_9001b4f4-1205-4755-8d15-fd442b51fa23" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_5534e237-ecea-4f5c-a9fb-8d611cccf378" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_9001b4f4-1205-4755-8d15-fd442b51fa23" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_7e6b0e94-3d0e-4ec4-b3b5-f2aeffa46c99" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_9001b4f4-1205-4755-8d15-fd442b51fa23" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_7e6b0e94-3d0e-4ec4-b3b5-f2aeffa46c99" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_e2f86016-a021-44d4-b96b-33c61b9c8331" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_9001b4f4-1205-4755-8d15-fd442b51fa23" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_e2f86016-a021-44d4-b96b-33c61b9c8331" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_1cf55c47-4888-48fb-9588-c952f799e8cd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_9001b4f4-1205-4755-8d15-fd442b51fa23" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_1cf55c47-4888-48fb-9588-c952f799e8cd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_a61e5c1a-ffe6-4c60-a968-e9a54b540b78" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_071b5d70-c4ea-480d-bbf2-4a64a950ad52" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_a61e5c1a-ffe6-4c60-a968-e9a54b540b78" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_a61e5c1a-ffe6-4c60-a968-e9a54b540b78_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_a61e5c1a-ffe6-4c60-a968-e9a54b540b78" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_a61e5c1a-ffe6-4c60-a968-e9a54b540b78_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_6827bb7f-c584-4695-b20f-c76adfadc0ff" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_a61e5c1a-ffe6-4c60-a968-e9a54b540b78" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_6827bb7f-c584-4695-b20f-c76adfadc0ff" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommodityContractMember_c637571e-9443-4267-a2eb-f81a3b5984b1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommodityContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_6827bb7f-c584-4695-b20f-c76adfadc0ff" xlink:to="loc_us-gaap_CommodityContractMember_c637571e-9443-4267-a2eb-f81a3b5984b1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateContractMember_2b05ae2a-acc3-4bbf-a563-74e08643d64c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestRateContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_6827bb7f-c584-4695-b20f-c76adfadc0ff" xlink:to="loc_us-gaap_InterestRateContractMember_2b05ae2a-acc3-4bbf-a563-74e08643d64c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmbeddedDerivativeFinancialInstrumentsMember_537a99b6-e982-40b5-aeab-53ace7df4360" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EmbeddedDerivativeFinancialInstrumentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_6827bb7f-c584-4695-b20f-c76adfadc0ff" xlink:to="loc_us-gaap_EmbeddedDerivativeFinancialInstrumentsMember_537a99b6-e982-40b5-aeab-53ace7df4360" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/LeasesNarrativeInformationDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#LeasesNarrativeInformationDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/LeasesNarrativeInformationDetails" xlink:type="extended" id="i614c0c232bde49a99282b55496ac9e77_LeasesNarrativeInformationDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionLineItems_66cfd3b0-42e4-4e95-8534-a8a159c3fef5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeLeaseDescriptionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_02b280b0-a0e4-4a4f-a07e-8e9199d5f271" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_66cfd3b0-42e4-4e95-8534-a8a159c3fef5" xlink:to="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_02b280b0-a0e4-4a4f-a07e-8e9199d5f271" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_LesseeLeasesTermOfContract_8dcd055e-f2a6-4610-ad2c-bbf40eaf01ee" xlink:href="paa-20211231.xsd#paa_LesseeLeasesTermOfContract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_66cfd3b0-42e4-4e95-8534-a8a159c3fef5" xlink:to="loc_paa_LesseeLeasesTermOfContract_8dcd055e-f2a6-4610-ad2c-bbf40eaf01ee" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_LesseeLeasesRenewalTerm_d820f868-3b0a-4cba-9a87-efcda9915d6b" xlink:href="paa-20211231.xsd#paa_LesseeLeasesRenewalTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_66cfd3b0-42e4-4e95-8534-a8a159c3fef5" xlink:to="loc_paa_LesseeLeasesRenewalTerm_d820f868-3b0a-4cba-9a87-efcda9915d6b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionTable_eb35661e-2c6d-4958-bd96-59058acafaf1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeLeaseDescriptionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_66cfd3b0-42e4-4e95-8534-a8a159c3fef5" xlink:to="loc_us-gaap_LesseeLeaseDescriptionTable_eb35661e-2c6d-4958-bd96-59058acafaf1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_78cacb66-a41b-495f-86dd-e30033fe9ccb" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_eb35661e-2c6d-4958-bd96-59058acafaf1" xlink:to="loc_srt_RangeAxis_78cacb66-a41b-495f-86dd-e30033fe9ccb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_78cacb66-a41b-495f-86dd-e30033fe9ccb_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_78cacb66-a41b-495f-86dd-e30033fe9ccb" xlink:to="loc_srt_RangeMember_78cacb66-a41b-495f-86dd-e30033fe9ccb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_faa26e7e-cdb8-4e1c-8d8f-9947ccbc72e1" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_78cacb66-a41b-495f-86dd-e30033fe9ccb" xlink:to="loc_srt_RangeMember_faa26e7e-cdb8-4e1c-8d8f-9947ccbc72e1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_3ac3dd95-4724-4173-9010-93f98f7a10a0" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_faa26e7e-cdb8-4e1c-8d8f-9947ccbc72e1" xlink:to="loc_srt_MinimumMember_3ac3dd95-4724-4173-9010-93f98f7a10a0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_85c61cee-0ea1-4e27-a325-1d73f57367ac" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_faa26e7e-cdb8-4e1c-8d8f-9947ccbc72e1" xlink:to="loc_srt_MaximumMember_85c61cee-0ea1-4e27-a325-1d73f57367ac" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_d5db5162-43a4-43ce-8e8d-f66c04b84363" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_eb35661e-2c6d-4958-bd96-59058acafaf1" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_d5db5162-43a4-43ce-8e8d-f66c04b84363" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_d5db5162-43a4-43ce-8e8d-f66c04b84363_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_d5db5162-43a4-43ce-8e8d-f66c04b84363" xlink:to="loc_us-gaap_RelatedPartyDomain_d5db5162-43a4-43ce-8e8d-f66c04b84363_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_e35ef1bb-58bf-43bf-a457-e29fdee70ef1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_d5db5162-43a4-43ce-8e8d-f66c04b84363" xlink:to="loc_us-gaap_RelatedPartyDomain_e35ef1bb-58bf-43bf-a457-e29fdee70ef1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvesteeMember_253d95db-bcf3-47b2-8449-8789708c3958" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityMethodInvesteeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_e35ef1bb-58bf-43bf-a457-e29fdee70ef1" xlink:to="loc_us-gaap_EquityMethodInvesteeMember_253d95db-bcf3-47b2-8449-8789708c3958" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsAxis_93b74e66-e1aa-4a68-abdf-41b6ac794a39" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherCommitmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_eb35661e-2c6d-4958-bd96-59058acafaf1" xlink:to="loc_us-gaap_OtherCommitmentsAxis_93b74e66-e1aa-4a68-abdf-41b6ac794a39" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsDomain_93b74e66-e1aa-4a68-abdf-41b6ac794a39_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherCommitmentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_OtherCommitmentsAxis_93b74e66-e1aa-4a68-abdf-41b6ac794a39" xlink:to="loc_us-gaap_OtherCommitmentsDomain_93b74e66-e1aa-4a68-abdf-41b6ac794a39_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsDomain_82ba4562-aca9-4f2d-910d-7016b9d76692" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherCommitmentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_OtherCommitmentsAxis_93b74e66-e1aa-4a68-abdf-41b6ac794a39" xlink:to="loc_us-gaap_OtherCommitmentsDomain_82ba4562-aca9-4f2d-910d-7016b9d76692" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_AgreementsToUtilizeAssetsOfEquityMethodInvesteesMember_6926374a-a638-48cc-a986-daf37107be9a" xlink:href="paa-20211231.xsd#paa_AgreementsToUtilizeAssetsOfEquityMethodInvesteesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsDomain_82ba4562-aca9-4f2d-910d-7016b9d76692" xlink:to="loc_paa_AgreementsToUtilizeAssetsOfEquityMethodInvesteesMember_6926374a-a638-48cc-a986-daf37107be9a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorLeaseDescriptionLineItems_e30117c5-ee78-4836-974b-5da91ac86fd5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LessorLeaseDescriptionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeaseTermOfContract_40316170-70b5-463b-b67b-1612b85e0bea" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LessorOperatingLeaseTermOfContract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_e30117c5-ee78-4836-974b-5da91ac86fd5" xlink:to="loc_us-gaap_LessorOperatingLeaseTermOfContract_40316170-70b5-463b-b67b-1612b85e0bea" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorLeaseDescriptionTable_2b8d0cc7-a9b9-44ff-877d-75668331c3eb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LessorLeaseDescriptionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_e30117c5-ee78-4836-974b-5da91ac86fd5" xlink:to="loc_us-gaap_LessorLeaseDescriptionTable_2b8d0cc7-a9b9-44ff-877d-75668331c3eb" xlink:type="arc" order="2" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_33f5cab3-d7ed-48c6-b8d8-3401b7637bfd" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LessorLeaseDescriptionTable_2b8d0cc7-a9b9-44ff-877d-75668331c3eb" xlink:to="loc_srt_RangeAxis_33f5cab3-d7ed-48c6-b8d8-3401b7637bfd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_33f5cab3-d7ed-48c6-b8d8-3401b7637bfd_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_2512702c-24cf-40a3-959d-b42940ea4039" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_336c3a62-a315-4c6a-af37-d1dfa38188cc" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MinimumMember"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_5dcf14dc-dd9a-4f6c-be5c-a5a36d9c531f" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/LeasesLeaseCostsDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#LeasesLeaseCostsDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/LeasesLeaseCostsDetails" xlink:type="extended" id="ie007d6a4e09a4f1f9d9240dc4e398cca_LeasesLeaseCostsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionLineItems_1dc316b7-cb37-46d2-9b2f-844ac615c2fc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeLeaseDescriptionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseCost_92e1f026-9dd8-4527-bb82-3a2fdc2b604e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_1dc316b7-cb37-46d2-9b2f-844ac615c2fc" xlink:to="loc_us-gaap_OperatingLeaseCost_92e1f026-9dd8-4527-bb82-3a2fdc2b604e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermLeaseCost_21c4ff73-b699-474f-8ba8-22aae99403e8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermLeaseCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_1dc316b7-cb37-46d2-9b2f-844ac615c2fc" xlink:to="loc_us-gaap_ShortTermLeaseCost_21c4ff73-b699-474f-8ba8-22aae99403e8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_OtherLeaseCost_5696145f-3032-4e83-ab8f-f1f793a33acd" xlink:href="paa-20211231.xsd#paa_OtherLeaseCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_1dc316b7-cb37-46d2-9b2f-844ac615c2fc" xlink:to="loc_paa_OtherLeaseCost_5696145f-3032-4e83-ab8f-f1f793a33acd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseCost_f088b604-5de6-4ce9-9df0-6a37e2b1c9bf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LeaseCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_1dc316b7-cb37-46d2-9b2f-844ac615c2fc" xlink:to="loc_us-gaap_LeaseCost_f088b604-5de6-4ce9-9df0-6a37e2b1c9bf" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_35c730c7-24b7-4439-b1b4-c38a39b2379b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_1dc316b7-cb37-46d2-9b2f-844ac615c2fc" xlink:to="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_35c730c7-24b7-4439-b1b4-c38a39b2379b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionTable_022a17aa-9dac-4c95-bcfd-0b4cd007fef5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeLeaseDescriptionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_1dc316b7-cb37-46d2-9b2f-844ac615c2fc" xlink:to="loc_us-gaap_LesseeLeaseDescriptionTable_022a17aa-9dac-4c95-bcfd-0b4cd007fef5" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsAxis_4d11ffe4-4f09-439a-9119-b0fe02896915" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherCommitmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_022a17aa-9dac-4c95-bcfd-0b4cd007fef5" xlink:to="loc_us-gaap_OtherCommitmentsAxis_4d11ffe4-4f09-439a-9119-b0fe02896915" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsDomain_4d11ffe4-4f09-439a-9119-b0fe02896915_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherCommitmentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_OtherCommitmentsAxis_4d11ffe4-4f09-439a-9119-b0fe02896915" xlink:to="loc_us-gaap_OtherCommitmentsDomain_4d11ffe4-4f09-439a-9119-b0fe02896915_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsDomain_677ee379-bde3-4b09-bdbd-2a8bc4617f6e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherCommitmentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_OtherCommitmentsAxis_4d11ffe4-4f09-439a-9119-b0fe02896915" xlink:to="loc_us-gaap_OtherCommitmentsDomain_677ee379-bde3-4b09-bdbd-2a8bc4617f6e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_AgreementsToUtilizeAssetsOfEquityMethodInvesteesMember_05e62d7e-e4e1-48be-96a2-a1612c471854" xlink:href="paa-20211231.xsd#paa_AgreementsToUtilizeAssetsOfEquityMethodInvesteesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsDomain_677ee379-bde3-4b09-bdbd-2a8bc4617f6e" xlink:to="loc_paa_AgreementsToUtilizeAssetsOfEquityMethodInvesteesMember_05e62d7e-e4e1-48be-96a2-a1612c471854" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_07d98e64-0d3d-4a2b-8dcc-1ac795d60b31" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_022a17aa-9dac-4c95-bcfd-0b4cd007fef5" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_07d98e64-0d3d-4a2b-8dcc-1ac795d60b31" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_07d98e64-0d3d-4a2b-8dcc-1ac795d60b31_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_07d98e64-0d3d-4a2b-8dcc-1ac795d60b31" xlink:to="loc_us-gaap_RelatedPartyDomain_07d98e64-0d3d-4a2b-8dcc-1ac795d60b31_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_297df619-29d1-4cb2-a136-2455a72f415e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_07d98e64-0d3d-4a2b-8dcc-1ac795d60b31" xlink:to="loc_us-gaap_RelatedPartyDomain_297df619-29d1-4cb2-a136-2455a72f415e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvesteeMember_c077ead1-6f4b-453d-992a-ae89affa0462" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityMethodInvesteeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_297df619-29d1-4cb2-a136-2455a72f415e" xlink:to="loc_us-gaap_EquityMethodInvesteeMember_c077ead1-6f4b-453d-992a-ae89affa0462" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/LeasesOtherInformationDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#LeasesOtherInformationDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/LeasesOtherInformationDetails" xlink:type="extended" id="id8a1fb4fe68545cc9de80a3674373980_LeasesOtherInformationDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionLineItems_47206a10-c02b-418d-917d-bcf916b84e95" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeLeaseDescriptionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeasePayments_3f89cdea-9d3a-4f9b-90d4-9836b0bb62d4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeasePayments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_47206a10-c02b-418d-917d-bcf916b84e95" xlink:to="loc_us-gaap_OperatingLeasePayments_3f89cdea-9d3a-4f9b-90d4-9836b0bb62d4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseInterestPaymentOnLiability_bd06b968-795e-4492-8919-925a785aef42" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseInterestPaymentOnLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_47206a10-c02b-418d-917d-bcf916b84e95" xlink:to="loc_us-gaap_FinanceLeaseInterestPaymentOnLiability_bd06b968-795e-4492-8919-925a785aef42" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeasePrincipalPayments_0201d7d2-e847-4d57-a90d-d48aada41a50" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeasePrincipalPayments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_47206a10-c02b-418d-917d-bcf916b84e95" xlink:to="loc_us-gaap_FinanceLeasePrincipalPayments_0201d7d2-e847-4d57-a90d-d48aada41a50" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability_7d007b02-a7f3-445e-9426-64b9c09e1ef1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_47206a10-c02b-418d-917d-bcf916b84e95" xlink:to="loc_us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability_7d007b02-a7f3-445e-9426-64b9c09e1ef1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability_c9df1e54-fce0-41ee-b081-950f4543a1cd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_47206a10-c02b-418d-917d-bcf916b84e95" xlink:to="loc_us-gaap_RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability_c9df1e54-fce0-41ee-b081-950f4543a1cd" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_38e7307b-6773-4511-bd36-1b55f7300214" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_47206a10-c02b-418d-917d-bcf916b84e95" xlink:to="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_38e7307b-6773-4511-bd36-1b55f7300214" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionTable_38436532-5e4c-460a-a1a3-ccfaa3eb967a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeLeaseDescriptionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_47206a10-c02b-418d-917d-bcf916b84e95" xlink:to="loc_us-gaap_LesseeLeaseDescriptionTable_38436532-5e4c-460a-a1a3-ccfaa3eb967a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_dde631b4-4fb7-476d-be8d-2eadbfa9f8ef" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_38436532-5e4c-460a-a1a3-ccfaa3eb967a" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_dde631b4-4fb7-476d-be8d-2eadbfa9f8ef" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_dde631b4-4fb7-476d-be8d-2eadbfa9f8ef_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_dde631b4-4fb7-476d-be8d-2eadbfa9f8ef" xlink:to="loc_us-gaap_RelatedPartyDomain_dde631b4-4fb7-476d-be8d-2eadbfa9f8ef_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_434014fc-5e70-4a8c-bfd8-253ff79d8d68" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_dde631b4-4fb7-476d-be8d-2eadbfa9f8ef" xlink:to="loc_us-gaap_RelatedPartyDomain_434014fc-5e70-4a8c-bfd8-253ff79d8d68" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvesteeMember_1fe55a43-69c8-41f5-9f33-673dc6b9e180" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityMethodInvesteeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_434014fc-5e70-4a8c-bfd8-253ff79d8d68" xlink:to="loc_us-gaap_EquityMethodInvesteeMember_1fe55a43-69c8-41f5-9f33-673dc6b9e180" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsAxis_d46f0c1e-3535-48d6-a00c-0c22cd4dd06e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherCommitmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_38436532-5e4c-460a-a1a3-ccfaa3eb967a" xlink:to="loc_us-gaap_OtherCommitmentsAxis_d46f0c1e-3535-48d6-a00c-0c22cd4dd06e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsDomain_d46f0c1e-3535-48d6-a00c-0c22cd4dd06e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherCommitmentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_OtherCommitmentsAxis_d46f0c1e-3535-48d6-a00c-0c22cd4dd06e" xlink:to="loc_us-gaap_OtherCommitmentsDomain_d46f0c1e-3535-48d6-a00c-0c22cd4dd06e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsDomain_21c6262b-64b4-4af2-ac20-fe640e353dd8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherCommitmentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_OtherCommitmentsAxis_d46f0c1e-3535-48d6-a00c-0c22cd4dd06e" xlink:to="loc_us-gaap_OtherCommitmentsDomain_21c6262b-64b4-4af2-ac20-fe640e353dd8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_AgreementsToUtilizeAssetsOfEquityMethodInvesteesMember_0529e3c3-7ad2-489a-9e7a-a9ab9afaeb6a" xlink:href="paa-20211231.xsd#paa_AgreementsToUtilizeAssetsOfEquityMethodInvesteesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsDomain_21c6262b-64b4-4af2-ac20-fe640e353dd8" xlink:to="loc_paa_AgreementsToUtilizeAssetsOfEquityMethodInvesteesMember_0529e3c3-7ad2-489a-9e7a-a9ab9afaeb6a" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/LeasesAssetsandLiabilitiesDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#LeasesAssetsandLiabilitiesDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/LeasesAssetsandLiabilitiesDetails" xlink:type="extended" id="i0c48092a2fb04202b8dba7b198e103f1_LeasesAssetsandLiabilitiesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionLineItems_28dd3e29-4307-4553-81e7-eba4cef64fb3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeLeaseDescriptionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAsset_c92814a5-da5f-4b69-a263-ce8c3a767aab" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseRightOfUseAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_28dd3e29-4307-4553-81e7-eba4cef64fb3" xlink:to="loc_us-gaap_OperatingLeaseRightOfUseAsset_c92814a5-da5f-4b69-a263-ce8c3a767aab" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseRightOfUseAssetBeforeAccumulatedAmortization_20a78292-3052-447e-bc69-e01f1e4f10e4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseRightOfUseAssetBeforeAccumulatedAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_28dd3e29-4307-4553-81e7-eba4cef64fb3" xlink:to="loc_us-gaap_FinanceLeaseRightOfUseAssetBeforeAccumulatedAmortization_20a78292-3052-447e-bc69-e01f1e4f10e4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseRightOfUseAssetAccumulatedAmortization_e0341b04-9813-4be6-9f6e-0d33a892896d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseRightOfUseAssetAccumulatedAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_28dd3e29-4307-4553-81e7-eba4cef64fb3" xlink:to="loc_us-gaap_FinanceLeaseRightOfUseAssetAccumulatedAmortization_e0341b04-9813-4be6-9f6e-0d33a892896d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseRightOfUseAsset_ee793182-753d-48cf-b76b-d2e4b1b28610" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseRightOfUseAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_28dd3e29-4307-4553-81e7-eba4cef64fb3" xlink:to="loc_us-gaap_FinanceLeaseRightOfUseAsset_ee793182-753d-48cf-b76b-d2e4b1b28610" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList_d98350a5-fa56-4196-8412-ddcffcad467c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_28dd3e29-4307-4553-81e7-eba4cef64fb3" xlink:to="loc_us-gaap_FinanceLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList_d98350a5-fa56-4196-8412-ddcffcad467c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_LeasesRightOfUseAsset_7cfba166-215c-45dc-9f76-00de1a74e722" xlink:href="paa-20211231.xsd#paa_LeasesRightOfUseAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_28dd3e29-4307-4553-81e7-eba4cef64fb3" xlink:to="loc_paa_LeasesRightOfUseAsset_7cfba166-215c-45dc-9f76-00de1a74e722" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseDescriptionAbstract_1f70965f-b670-43fb-b89b-9888bf2af419" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeOperatingLeaseDescriptionAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_28dd3e29-4307-4553-81e7-eba4cef64fb3" xlink:to="loc_us-gaap_LesseeOperatingLeaseDescriptionAbstract_1f70965f-b670-43fb-b89b-9888bf2af419" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityCurrent_4d791a79-59b5-4876-8db1-4e1fef2e239d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseLiabilityCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeOperatingLeaseDescriptionAbstract_1f70965f-b670-43fb-b89b-9888bf2af419" xlink:to="loc_us-gaap_OperatingLeaseLiabilityCurrent_4d791a79-59b5-4876-8db1-4e1fef2e239d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityCurrentStatementOfFinancialPositionExtensibleList_6bd12d5d-1340-464b-a91d-6a355ef38713" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseLiabilityCurrentStatementOfFinancialPositionExtensibleList"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeOperatingLeaseDescriptionAbstract_1f70965f-b670-43fb-b89b-9888bf2af419" xlink:to="loc_us-gaap_OperatingLeaseLiabilityCurrentStatementOfFinancialPositionExtensibleList_6bd12d5d-1340-464b-a91d-6a355ef38713" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_02c05b06-509d-46c1-a663-40c658c95297" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseLiabilityNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeOperatingLeaseDescriptionAbstract_1f70965f-b670-43fb-b89b-9888bf2af419" xlink:to="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_02c05b06-509d-46c1-a663-40c658c95297" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiability_d055e43e-16b5-4781-9dce-f65df143a7cc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeOperatingLeaseDescriptionAbstract_1f70965f-b670-43fb-b89b-9888bf2af419" xlink:to="loc_us-gaap_OperatingLeaseLiability_d055e43e-16b5-4781-9dce-f65df143a7cc" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeFinanceLeaseDescriptionAbstract_f9eadc14-2b57-4601-8db5-b041f88d187b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeFinanceLeaseDescriptionAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_28dd3e29-4307-4553-81e7-eba4cef64fb3" xlink:to="loc_us-gaap_LesseeFinanceLeaseDescriptionAbstract_f9eadc14-2b57-4601-8db5-b041f88d187b" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityCurrent_908b23fe-0d86-4b60-b4cb-1cf969dd74bb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseLiabilityCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeFinanceLeaseDescriptionAbstract_f9eadc14-2b57-4601-8db5-b041f88d187b" xlink:to="loc_us-gaap_FinanceLeaseLiabilityCurrent_908b23fe-0d86-4b60-b4cb-1cf969dd74bb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityCurrentStatementOfFinancialPositionExtensibleList_22f6ae22-6184-4cf2-8f1c-05eba22ebb64" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseLiabilityCurrentStatementOfFinancialPositionExtensibleList"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeFinanceLeaseDescriptionAbstract_f9eadc14-2b57-4601-8db5-b041f88d187b" xlink:to="loc_us-gaap_FinanceLeaseLiabilityCurrentStatementOfFinancialPositionExtensibleList_22f6ae22-6184-4cf2-8f1c-05eba22ebb64" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityNoncurrent_1de8fa5f-2292-406c-88fa-00bb06b4ffde" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseLiabilityNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeFinanceLeaseDescriptionAbstract_f9eadc14-2b57-4601-8db5-b041f88d187b" xlink:to="loc_us-gaap_FinanceLeaseLiabilityNoncurrent_1de8fa5f-2292-406c-88fa-00bb06b4ffde" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityNoncurrentStatementOfFinancialPositionExtensibleList_e2dc5dde-d441-4f2c-b280-f465e646143f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseLiabilityNoncurrentStatementOfFinancialPositionExtensibleList"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeFinanceLeaseDescriptionAbstract_f9eadc14-2b57-4601-8db5-b041f88d187b" xlink:to="loc_us-gaap_FinanceLeaseLiabilityNoncurrentStatementOfFinancialPositionExtensibleList_e2dc5dde-d441-4f2c-b280-f465e646143f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiability_ed1185d0-a3dc-4339-8683-61f0ae028b9c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeFinanceLeaseDescriptionAbstract_f9eadc14-2b57-4601-8db5-b041f88d187b" xlink:to="loc_us-gaap_FinanceLeaseLiability_ed1185d0-a3dc-4339-8683-61f0ae028b9c" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_LeasesLiability_2fe60037-f92e-46cd-b937-cb4c5900a94d" xlink:href="paa-20211231.xsd#paa_LeasesLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_28dd3e29-4307-4553-81e7-eba4cef64fb3" xlink:to="loc_paa_LeasesLiability_2fe60037-f92e-46cd-b937-cb4c5900a94d" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_6670c89e-4e12-436c-9f1a-a7e6ca91d71d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_28dd3e29-4307-4553-81e7-eba4cef64fb3" xlink:to="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_6670c89e-4e12-436c-9f1a-a7e6ca91d71d" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionTable_133cfddf-c726-4573-822b-9026c2ae2409" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeLeaseDescriptionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_28dd3e29-4307-4553-81e7-eba4cef64fb3" xlink:to="loc_us-gaap_LesseeLeaseDescriptionTable_133cfddf-c726-4573-822b-9026c2ae2409" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_e3949450-5070-47a0-adf2-eb29c206429d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_133cfddf-c726-4573-822b-9026c2ae2409" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_e3949450-5070-47a0-adf2-eb29c206429d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_e3949450-5070-47a0-adf2-eb29c206429d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_e3949450-5070-47a0-adf2-eb29c206429d" xlink:to="loc_us-gaap_RelatedPartyDomain_e3949450-5070-47a0-adf2-eb29c206429d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_a02557c2-3b68-471a-ae4d-8539fc429b52" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_e3949450-5070-47a0-adf2-eb29c206429d" xlink:to="loc_us-gaap_RelatedPartyDomain_a02557c2-3b68-471a-ae4d-8539fc429b52" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvesteeMember_eac54077-f39d-4eb9-8554-465fb532cf79" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityMethodInvesteeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_a02557c2-3b68-471a-ae4d-8539fc429b52" xlink:to="loc_us-gaap_EquityMethodInvesteeMember_eac54077-f39d-4eb9-8554-465fb532cf79" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsAxis_35ae69c7-7328-43c7-928a-a16821cba2cf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherCommitmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_133cfddf-c726-4573-822b-9026c2ae2409" xlink:to="loc_us-gaap_OtherCommitmentsAxis_35ae69c7-7328-43c7-928a-a16821cba2cf" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsDomain_35ae69c7-7328-43c7-928a-a16821cba2cf_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherCommitmentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_OtherCommitmentsAxis_35ae69c7-7328-43c7-928a-a16821cba2cf" xlink:to="loc_us-gaap_OtherCommitmentsDomain_35ae69c7-7328-43c7-928a-a16821cba2cf_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsDomain_0738f709-c0c9-4e49-9db6-d65513de5be8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherCommitmentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_OtherCommitmentsAxis_35ae69c7-7328-43c7-928a-a16821cba2cf" xlink:to="loc_us-gaap_OtherCommitmentsDomain_0738f709-c0c9-4e49-9db6-d65513de5be8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_AgreementsToUtilizeAssetsOfEquityMethodInvesteesMember_0e08c9a2-e722-4b89-b251-159d8fbc57b3" xlink:href="paa-20211231.xsd#paa_AgreementsToUtilizeAssetsOfEquityMethodInvesteesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsDomain_0738f709-c0c9-4e49-9db6-d65513de5be8" xlink:to="loc_paa_AgreementsToUtilizeAssetsOfEquityMethodInvesteesMember_0e08c9a2-e722-4b89-b251-159d8fbc57b3" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/LeasesMaturityofLeaseLiabilitiesDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#LeasesMaturityofLeaseLiabilitiesDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/LeasesMaturityofLeaseLiabilitiesDetails" xlink:type="extended" id="i8a0e9779dc4e4dbe9dd7ddf087599b43_LeasesMaturityofLeaseLiabilitiesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionLineItems_95514eb5-5499-41c1-a708-24fda23731ed" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeLeaseDescriptionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_7c2ec096-ed64-4449-9c5a-45859b0a2376" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_95514eb5-5499-41c1-a708-24fda23731ed" xlink:to="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_7c2ec096-ed64-4449-9c5a-45859b0a2376" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_ae58b276-40e2-4973-ab0d-57cf396f3549" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_7c2ec096-ed64-4449-9c5a-45859b0a2376" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_ae58b276-40e2-4973-ab0d-57cf396f3549" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo_3c49163f-2f72-4205-8c93-326e23a3839e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_7c2ec096-ed64-4449-9c5a-45859b0a2376" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo_3c49163f-2f72-4205-8c93-326e23a3839e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree_36e417f0-7868-47d9-9ac8-8b7fd3bd56d0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_7c2ec096-ed64-4449-9c5a-45859b0a2376" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree_36e417f0-7868-47d9-9ac8-8b7fd3bd56d0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour_c8757d35-fd38-47f0-9a10-9b60af9dfba1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_7c2ec096-ed64-4449-9c5a-45859b0a2376" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour_c8757d35-fd38-47f0-9a10-9b60af9dfba1" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive_11edfeef-e83f-43d2-9373-9c54cb48b431" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_7c2ec096-ed64-4449-9c5a-45859b0a2376" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive_11edfeef-e83f-43d2-9373-9c54cb48b431" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive_bb9047f2-d216-4d38-84d3-8975df3ebfa2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_7c2ec096-ed64-4449-9c5a-45859b0a2376" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive_bb9047f2-d216-4d38-84d3-8975df3ebfa2" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_96090215-a30c-452d-bbe5-d5168a1ff703" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_7c2ec096-ed64-4449-9c5a-45859b0a2376" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_96090215-a30c-452d-bbe5-d5168a1ff703" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_ca933e07-c7cf-4fcc-81bc-df1b9b9febd0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_7c2ec096-ed64-4449-9c5a-45859b0a2376" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_ca933e07-c7cf-4fcc-81bc-df1b9b9febd0" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiability_8a98f2c5-9c3c-4bb9-ba6f-b41ae3198814" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_7c2ec096-ed64-4449-9c5a-45859b0a2376" xlink:to="loc_us-gaap_OperatingLeaseLiability_8a98f2c5-9c3c-4bb9-ba6f-b41ae3198814" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract_f97b4e10-7c82-45e9-886d-04b8edc904d4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_95514eb5-5499-41c1-a708-24fda23731ed" xlink:to="loc_us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract_f97b4e10-7c82-45e9-886d-04b8edc904d4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueNextTwelveMonths_4d8c6d06-a008-4d0d-a0ee-3d60cfbec9cf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDueNextTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract_f97b4e10-7c82-45e9-886d-04b8edc904d4" xlink:to="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueNextTwelveMonths_4d8c6d06-a008-4d0d-a0ee-3d60cfbec9cf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueYearTwo_fb9961b1-7529-45fa-8dbd-a1f3ab47f0b4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDueYearTwo"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract_f97b4e10-7c82-45e9-886d-04b8edc904d4" xlink:to="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueYearTwo_fb9961b1-7529-45fa-8dbd-a1f3ab47f0b4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueYearThree_bf7cdce4-cabb-43c9-803b-317ce001e54f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDueYearThree"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract_f97b4e10-7c82-45e9-886d-04b8edc904d4" xlink:to="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueYearThree_bf7cdce4-cabb-43c9-803b-317ce001e54f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFour_08a4e5df-57c4-4fcb-8ecf-bda3e8054600" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDueYearFour"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract_f97b4e10-7c82-45e9-886d-04b8edc904d4" xlink:to="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFour_08a4e5df-57c4-4fcb-8ecf-bda3e8054600" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFive_b412c176-9852-4d5a-9999-b4f587fbb6c0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDueYearFive"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract_f97b4e10-7c82-45e9-886d-04b8edc904d4" xlink:to="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFive_b412c176-9852-4d5a-9999-b4f587fbb6c0" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueAfterYearFive_1f56cf71-2e6f-4f64-9cc3-cda4d0108c2c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDueAfterYearFive"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract_f97b4e10-7c82-45e9-886d-04b8edc904d4" xlink:to="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueAfterYearFive_1f56cf71-2e6f-4f64-9cc3-cda4d0108c2c" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityPaymentsDue_58532a60-1992-4874-963c-52125e19018f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract_f97b4e10-7c82-45e9-886d-04b8edc904d4" xlink:to="loc_us-gaap_FinanceLeaseLiabilityPaymentsDue_58532a60-1992-4874-963c-52125e19018f" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount_2f825141-b511-44ab-9ace-d666a301b4f9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract_f97b4e10-7c82-45e9-886d-04b8edc904d4" xlink:to="loc_us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount_2f825141-b511-44ab-9ace-d666a301b4f9" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiability_04fe3ebc-f588-4fe0-b9ad-6553128b3236" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract_f97b4e10-7c82-45e9-886d-04b8edc904d4" xlink:to="loc_us-gaap_FinanceLeaseLiability_04fe3ebc-f588-4fe0-b9ad-6553128b3236" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_77d4d559-fa68-4344-a714-4528f6b7319b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract_f97b4e10-7c82-45e9-886d-04b8edc904d4" xlink:to="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_77d4d559-fa68-4344-a714-4528f6b7319b" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionTable_5a8c96b3-82da-4559-9fcf-86907fc345ac" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeLeaseDescriptionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_95514eb5-5499-41c1-a708-24fda23731ed" xlink:to="loc_us-gaap_LesseeLeaseDescriptionTable_5a8c96b3-82da-4559-9fcf-86907fc345ac" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_d7fd09d2-1de2-4787-97c5-d8000a0a4dff" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_5a8c96b3-82da-4559-9fcf-86907fc345ac" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_d7fd09d2-1de2-4787-97c5-d8000a0a4dff" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_d7fd09d2-1de2-4787-97c5-d8000a0a4dff_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_d7fd09d2-1de2-4787-97c5-d8000a0a4dff" xlink:to="loc_us-gaap_RelatedPartyDomain_d7fd09d2-1de2-4787-97c5-d8000a0a4dff_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_4cc31c64-579d-48bf-9679-f83cf88c1052" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_d7fd09d2-1de2-4787-97c5-d8000a0a4dff" xlink:to="loc_us-gaap_RelatedPartyDomain_4cc31c64-579d-48bf-9679-f83cf88c1052" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvesteeMember_4edef72c-31c3-46f3-905c-ca0f01a5e6dd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityMethodInvesteeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_4cc31c64-579d-48bf-9679-f83cf88c1052" xlink:to="loc_us-gaap_EquityMethodInvesteeMember_4edef72c-31c3-46f3-905c-ca0f01a5e6dd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsAxis_283901e2-40c7-42ae-b5d2-dcf37275e1c9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherCommitmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_5a8c96b3-82da-4559-9fcf-86907fc345ac" xlink:to="loc_us-gaap_OtherCommitmentsAxis_283901e2-40c7-42ae-b5d2-dcf37275e1c9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsDomain_283901e2-40c7-42ae-b5d2-dcf37275e1c9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherCommitmentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_OtherCommitmentsAxis_283901e2-40c7-42ae-b5d2-dcf37275e1c9" xlink:to="loc_us-gaap_OtherCommitmentsDomain_283901e2-40c7-42ae-b5d2-dcf37275e1c9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsDomain_c87d6dcc-0008-4124-b00a-bca1ae8b7fee" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherCommitmentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_OtherCommitmentsAxis_283901e2-40c7-42ae-b5d2-dcf37275e1c9" xlink:to="loc_us-gaap_OtherCommitmentsDomain_c87d6dcc-0008-4124-b00a-bca1ae8b7fee" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_AgreementsToUtilizeAssetsOfEquityMethodInvesteesMember_9d851882-2a52-4490-bf94-75bc6e030a82" xlink:href="paa-20211231.xsd#paa_AgreementsToUtilizeAssetsOfEquityMethodInvesteesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsDomain_c87d6dcc-0008-4124-b00a-bca1ae8b7fee" xlink:to="loc_paa_AgreementsToUtilizeAssetsOfEquityMethodInvesteesMember_9d851882-2a52-4490-bf94-75bc6e030a82" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/IncomeTaxesReconciliationandDeferredTaxAssetsDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#IncomeTaxesReconciliationandDeferredTaxAssetsDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/IncomeTaxesReconciliationandDeferredTaxAssetsDetails" xlink:type="extended" id="i7ecc8c5fc5ba40f486df8f5e220209c8_IncomeTaxesReconciliationandDeferredTaxAssetsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExaminationLineItems_92feca1a-dcf6-4978-9220-ad8f21d7f030" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxExaminationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_8290d0e3-e724-4e89-9a50-e90428cb5def" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxExaminationLineItems_92feca1a-dcf6-4978-9220-ad8f21d7f030" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_8290d0e3-e724-4e89-9a50-e90428cb5def" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_IncomeNotSubjectToForeignTax_ee6ab913-7d75-43a8-9871-98a42e88aacf" xlink:href="paa-20211231.xsd#paa_IncomeNotSubjectToForeignTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxExaminationLineItems_92feca1a-dcf6-4978-9220-ad8f21d7f030" xlink:to="loc_paa_IncomeNotSubjectToForeignTax_ee6ab913-7d75-43a8-9871-98a42e88aacf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_IncomeSubjectToForeignTax_40210284-c3a7-4435-96ac-a5d6fea5583e" xlink:href="paa-20211231.xsd#paa_IncomeSubjectToForeignTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxExaminationLineItems_92feca1a-dcf6-4978-9220-ad8f21d7f030" xlink:to="loc_paa_IncomeSubjectToForeignTax_40210284-c3a7-4435-96ac-a5d6fea5583e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_ForeignTaxRate_88c88c0a-7029-4b0c-94fe-e7ab85998333" xlink:href="paa-20211231.xsd#paa_ForeignTaxRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxExaminationLineItems_92feca1a-dcf6-4978-9220-ad8f21d7f030" xlink:to="loc_paa_ForeignTaxRate_88c88c0a-7029-4b0c-94fe-e7ab85998333" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_ForeignIncomeTaxExpenseBenefitAtForeignStatutoryRate_7e5032a6-65bb-4f4f-8002-158eb1caf096" xlink:href="paa-20211231.xsd#paa_ForeignIncomeTaxExpenseBenefitAtForeignStatutoryRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxExaminationLineItems_92feca1a-dcf6-4978-9220-ad8f21d7f030" xlink:to="loc_paa_ForeignIncomeTaxExpenseBenefitAtForeignStatutoryRate_7e5032a6-65bb-4f4f-8002-158eb1caf096" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_ForeignPeriodTaxOnPermanentBookVersusTaxDifferencesAndRateChanges_3e36e9ee-f170-4d93-bc7b-87e4cd2a45dd" xlink:href="paa-20211231.xsd#paa_ForeignPeriodTaxOnPermanentBookVersusTaxDifferencesAndRateChanges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxExaminationLineItems_92feca1a-dcf6-4978-9220-ad8f21d7f030" xlink:to="loc_paa_ForeignPeriodTaxOnPermanentBookVersusTaxDifferencesAndRateChanges_3e36e9ee-f170-4d93-bc7b-87e4cd2a45dd" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CurrentStateAndLocalTaxExpenseBenefit_8ff9653d-426e-453b-9c60-de74bc108c4b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CurrentStateAndLocalTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxExaminationLineItems_92feca1a-dcf6-4978-9220-ad8f21d7f030" xlink:to="loc_us-gaap_CurrentStateAndLocalTaxExpenseBenefit_8ff9653d-426e-453b-9c60-de74bc108c4b" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_d72c466a-592e-4480-8582-0922f55b725d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxExaminationLineItems_92feca1a-dcf6-4978-9220-ad8f21d7f030" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_d72c466a-592e-4480-8582-0922f55b725d" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComponentsOfDeferredTaxAssetsAbstract_153d5322-e097-40d5-a266-e47c411281b9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ComponentsOfDeferredTaxAssetsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxExaminationLineItems_92feca1a-dcf6-4978-9220-ad8f21d7f030" xlink:to="loc_us-gaap_ComponentsOfDeferredTaxAssetsAbstract_153d5322-e097-40d5-a266-e47c411281b9" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsDerivativeInstruments_dccd812b-f0b5-4bd0-8199-56d12a05f2f2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxAssetsDerivativeInstruments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxAssetsAbstract_153d5322-e097-40d5-a266-e47c411281b9" xlink:to="loc_us-gaap_DeferredTaxAssetsDerivativeInstruments_dccd812b-f0b5-4bd0-8199-56d12a05f2f2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_DeferredTaxAssetsLeasingArrangements_77acfd01-a14d-46e5-aa9f-767ea2128f68" xlink:href="paa-20211231.xsd#paa_DeferredTaxAssetsLeasingArrangements"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxAssetsAbstract_153d5322-e097-40d5-a266-e47c411281b9" xlink:to="loc_paa_DeferredTaxAssetsLeasingArrangements_77acfd01-a14d-46e5-aa9f-767ea2128f68" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsOperatingLossCarryforwards_6a139c03-a814-4108-9c64-06a53f7fd523" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxAssetsOperatingLossCarryforwards"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxAssetsAbstract_153d5322-e097-40d5-a266-e47c411281b9" xlink:to="loc_us-gaap_DeferredTaxAssetsOperatingLossCarryforwards_6a139c03-a814-4108-9c64-06a53f7fd523" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsOther_bc42e912-ec00-4d24-8b12-b4f3a161a05e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxAssetsOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxAssetsAbstract_153d5322-e097-40d5-a266-e47c411281b9" xlink:to="loc_us-gaap_DeferredTaxAssetsOther_bc42e912-ec00-4d24-8b12-b4f3a161a05e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsNet_03eac781-2d7e-4586-a7e1-aa077bb40755" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxAssetsAbstract_153d5322-e097-40d5-a266-e47c411281b9" xlink:to="loc_us-gaap_DeferredTaxAssetsNet_03eac781-2d7e-4586-a7e1-aa077bb40755" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComponentsOfDeferredTaxLiabilitiesAbstract_b87c80c5-4d93-43c6-986d-71b9898735a6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ComponentsOfDeferredTaxLiabilitiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxExaminationLineItems_92feca1a-dcf6-4978-9220-ad8f21d7f030" xlink:to="loc_us-gaap_ComponentsOfDeferredTaxLiabilitiesAbstract_b87c80c5-4d93-43c6-986d-71b9898735a6" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment_12d8d896-77ab-4e8b-80ed-39b8e499e6b9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxLiabilitiesAbstract_b87c80c5-4d93-43c6-986d-71b9898735a6" xlink:to="loc_us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment_12d8d896-77ab-4e8b-80ed-39b8e499e6b9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxLiabilitiesLeasingArrangements_6d90dacb-2374-45c8-b3d2-09f7f02ea234" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxLiabilitiesLeasingArrangements"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxLiabilitiesAbstract_b87c80c5-4d93-43c6-986d-71b9898735a6" xlink:to="loc_us-gaap_DeferredTaxLiabilitiesLeasingArrangements_6d90dacb-2374-45c8-b3d2-09f7f02ea234" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxLiabilitiesOther_4b5ae8e6-7111-43d4-a2b4-c2fbffe883ea" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxLiabilitiesOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxLiabilitiesAbstract_b87c80c5-4d93-43c6-986d-71b9898735a6" xlink:to="loc_us-gaap_DeferredTaxLiabilitiesOther_4b5ae8e6-7111-43d4-a2b4-c2fbffe883ea" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxLiabilities_8cbf449f-73fa-4daa-8466-318b480946b6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredIncomeTaxLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxLiabilitiesAbstract_b87c80c5-4d93-43c6-986d-71b9898735a6" xlink:to="loc_us-gaap_DeferredIncomeTaxLiabilities_8cbf449f-73fa-4daa-8466-318b480946b6" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxLiabilities_fdc90f32-5c03-4bc5-ad34-cbdb5bf8c800" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxExaminationLineItems_92feca1a-dcf6-4978-9220-ad8f21d7f030" xlink:to="loc_us-gaap_DeferredTaxLiabilities_fdc90f32-5c03-4bc5-ad34-cbdb5bf8c800" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxAssetsNet_8b8d8800-74f2-468c-85a3-b73060b5cc7a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredIncomeTaxAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxExaminationLineItems_92feca1a-dcf6-4978-9220-ad8f21d7f030" xlink:to="loc_us-gaap_DeferredIncomeTaxAssetsNet_8b8d8800-74f2-468c-85a3-b73060b5cc7a" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxLiabilitiesNet_cee0697b-ac95-42d2-96f8-d9ccece62fd0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredIncomeTaxLiabilitiesNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxExaminationLineItems_92feca1a-dcf6-4978-9220-ad8f21d7f030" xlink:to="loc_us-gaap_DeferredIncomeTaxLiabilitiesNet_cee0697b-ac95-42d2-96f8-d9ccece62fd0" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExaminationTable_7c455bf9-452d-407c-ba31-01b136b246bd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxExaminationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_IncomeTaxExaminationLineItems_92feca1a-dcf6-4978-9220-ad8f21d7f030" xlink:to="loc_us-gaap_IncomeTaxExaminationTable_7c455bf9-452d-407c-ba31-01b136b246bd" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_7c18f1ca-9776-4dec-94a6-ff48dadb11cf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeTaxExaminationTable_7c455bf9-452d-407c-ba31-01b136b246bd" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_7c18f1ca-9776-4dec-94a6-ff48dadb11cf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_7c18f1ca-9776-4dec-94a6-ff48dadb11cf_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_7c18f1ca-9776-4dec-94a6-ff48dadb11cf" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_7c18f1ca-9776-4dec-94a6-ff48dadb11cf_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_e45bf60f-7eea-42ac-828a-7423922229b6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_7c18f1ca-9776-4dec-94a6-ff48dadb11cf" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_e45bf60f-7eea-42ac-828a-7423922229b6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNoncurrentAssetsMember_03315e2d-2fd7-45c5-8c45-f80d8f316a62" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherNoncurrentAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_e45bf60f-7eea-42ac-828a-7423922229b6" xlink:to="loc_us-gaap_OtherNoncurrentAssetsMember_03315e2d-2fd7-45c5-8c45-f80d8f316a62" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNoncurrentLiabilitiesMember_8f119da6-6a41-4f16-a8f7-ebd87507f16b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherNoncurrentLiabilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_e45bf60f-7eea-42ac-828a-7423922229b6" xlink:to="loc_us-gaap_OtherNoncurrentLiabilitiesMember_8f119da6-6a41-4f16-a8f7-ebd87507f16b" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/IncomeTaxesNarrativeDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#IncomeTaxesNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/IncomeTaxesNarrativeDetails" xlink:type="extended" id="i65727bef616848998aecba3028fe9d58_IncomeTaxesNarrativeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExaminationLineItems_d671f356-36c5-44e2-a267-403df6c0dece" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxExaminationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_ForeignTaxRate_9ebaf0ca-f57a-491b-9b88-53b8ea23b9bf" xlink:href="paa-20211231.xsd#paa_ForeignTaxRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxExaminationLineItems_d671f356-36c5-44e2-a267-403df6c0dece" xlink:to="loc_paa_ForeignTaxRate_9ebaf0ca-f57a-491b-9b88-53b8ea23b9bf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAdjustmentOfDeferredTaxAssetLiability_1a718d87-da3d-4b9b-ab3a-2516287a7506" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAdjustmentOfDeferredTaxAssetLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxExaminationLineItems_d671f356-36c5-44e2-a267-403df6c0dece" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAdjustmentOfDeferredTaxAssetLiability_1a718d87-da3d-4b9b-ab3a-2516287a7506" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLossCarryforwards_49933d0d-cc04-4ec5-9bbd-7a7b0f9579ed" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLossCarryforwards"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxExaminationLineItems_d671f356-36c5-44e2-a267-403df6c0dece" xlink:to="loc_us-gaap_OperatingLossCarryforwards_49933d0d-cc04-4ec5-9bbd-7a7b0f9579ed" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_IncomeTaxExaminationAmountofAssessmentDisputed_806b97a5-a168-4d47-9eaa-35af3f5f62bd" xlink:href="paa-20211231.xsd#paa_IncomeTaxExaminationAmountofAssessmentDisputed"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxExaminationLineItems_d671f356-36c5-44e2-a267-403df6c0dece" xlink:to="loc_paa_IncomeTaxExaminationAmountofAssessmentDisputed_806b97a5-a168-4d47-9eaa-35af3f5f62bd" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_IncomeTaxExaminationAmountofDisputedAssessmentPaid_63396aec-b159-4045-841f-f5dbd74d1c4e" xlink:href="paa-20211231.xsd#paa_IncomeTaxExaminationAmountofDisputedAssessmentPaid"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxExaminationLineItems_d671f356-36c5-44e2-a267-403df6c0dece" xlink:to="loc_paa_IncomeTaxExaminationAmountofDisputedAssessmentPaid_63396aec-b159-4045-841f-f5dbd74d1c4e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExaminationTable_4a823154-3f70-40de-8922-6ac0a721d54a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxExaminationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_IncomeTaxExaminationLineItems_d671f356-36c5-44e2-a267-403df6c0dece" xlink:to="loc_us-gaap_IncomeTaxExaminationTable_4a823154-3f70-40de-8922-6ac0a721d54a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityNameAxis_b3c53d65-3cbc-41b7-81be-976e4484a367" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxAuthorityNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeTaxExaminationTable_4a823154-3f70-40de-8922-6ac0a721d54a" xlink:to="loc_us-gaap_IncomeTaxAuthorityNameAxis_b3c53d65-3cbc-41b7-81be-976e4484a367" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityNameDomain_b3c53d65-3cbc-41b7-81be-976e4484a367_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxAuthorityNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeTaxAuthorityNameAxis_b3c53d65-3cbc-41b7-81be-976e4484a367" xlink:to="loc_us-gaap_IncomeTaxAuthorityNameDomain_b3c53d65-3cbc-41b7-81be-976e4484a367_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityNameDomain_daa2e3db-d76a-4d8c-803f-81b009f14f4b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxAuthorityNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeTaxAuthorityNameAxis_b3c53d65-3cbc-41b7-81be-976e4484a367" xlink:to="loc_us-gaap_IncomeTaxAuthorityNameDomain_daa2e3db-d76a-4d8c-803f-81b009f14f4b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_AlbertaGovernmentCanadaMember_222e14f1-fe02-4133-a795-33bc85ae9ca8" xlink:href="paa-20211231.xsd#paa_AlbertaGovernmentCanadaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityNameDomain_daa2e3db-d76a-4d8c-803f-81b009f14f4b" xlink:to="loc_paa_AlbertaGovernmentCanadaMember_222e14f1-fe02-4133-a795-33bc85ae9ca8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_CanadianTaxAuthoritiesMember_cd18c055-38b7-47e8-a982-e08d801602e0" xlink:href="paa-20211231.xsd#paa_CanadianTaxAuthoritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityNameDomain_daa2e3db-d76a-4d8c-803f-81b009f14f4b" xlink:to="loc_paa_CanadianTaxAuthoritiesMember_cd18c055-38b7-47e8-a982-e08d801602e0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_a88c8f56-ecda-45c8-8de4-8ff186154c52" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeTaxExaminationTable_4a823154-3f70-40de-8922-6ac0a721d54a" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_a88c8f56-ecda-45c8-8de4-8ff186154c52" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_a88c8f56-ecda-45c8-8de4-8ff186154c52_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_a88c8f56-ecda-45c8-8de4-8ff186154c52" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_a88c8f56-ecda-45c8-8de4-8ff186154c52_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_30c5b70c-8695-4dcf-a103-dcd94d2b34e6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_a88c8f56-ecda-45c8-8de4-8ff186154c52" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_30c5b70c-8695-4dcf-a103-dcd94d2b34e6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNoncurrentAssetsMember_8f0feb09-ba15-4ead-8844-fccf819bffc3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherNoncurrentAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_30c5b70c-8695-4dcf-a103-dcd94d2b34e6" xlink:to="loc_us-gaap_OtherNoncurrentAssetsMember_8f0feb09-ba15-4ead-8844-fccf819bffc3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityAxis_8da93bb5-d47b-4a2f-8bc3-1bd9ca19c093" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxAuthorityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeTaxExaminationTable_4a823154-3f70-40de-8922-6ac0a721d54a" xlink:to="loc_us-gaap_IncomeTaxAuthorityAxis_8da93bb5-d47b-4a2f-8bc3-1bd9ca19c093" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_8da93bb5-d47b-4a2f-8bc3-1bd9ca19c093_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxAuthorityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis_8da93bb5-d47b-4a2f-8bc3-1bd9ca19c093" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_8da93bb5-d47b-4a2f-8bc3-1bd9ca19c093_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_54dd66d5-4b4f-46c4-8caa-593c3efecbbc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxAuthorityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis_8da93bb5-d47b-4a2f-8bc3-1bd9ca19c093" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_54dd66d5-4b4f-46c4-8caa-593c3efecbbc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignCountryMember_99457fb6-2c16-496b-b418-6461c26e3add" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ForeignCountryMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_54dd66d5-4b4f-46c4-8caa-593c3efecbbc" xlink:to="loc_us-gaap_ForeignCountryMember_99457fb6-2c16-496b-b418-6461c26e3add" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/MajorCustomersandConcentrationofCreditRiskDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#MajorCustomersandConcentrationofCreditRiskDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/MajorCustomersandConcentrationofCreditRiskDetails" xlink:type="extended" id="i90eeb4cdf99b46f4aa370222348c00a7_MajorCustomersandConcentrationofCreditRiskDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskLineItems_f57d68e2-208c-4f3c-a980-f33c2b198eab" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_38f2077f-563d-49f4-a000-228aa5fd1046" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskPercentage1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_f57d68e2-208c-4f3c-a980-f33c2b198eab" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_38f2077f-563d-49f4-a000-228aa5fd1046" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTable_edb54ae5-434a-4a73-abcc-0385cc5ccd42" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_f57d68e2-208c-4f3c-a980-f33c2b198eab" xlink:to="loc_us-gaap_ConcentrationRiskTable_edb54ae5-434a-4a73-abcc-0385cc5ccd42" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_4207a68d-c93e-4097-93b8-88361e395789" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_edb54ae5-434a-4a73-abcc-0385cc5ccd42" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_4207a68d-c93e-4097-93b8-88361e395789" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_4207a68d-c93e-4097-93b8-88361e395789_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_4207a68d-c93e-4097-93b8-88361e395789" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_4207a68d-c93e-4097-93b8-88361e395789_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_c7a1ceb7-e039-450f-a18a-99c76a1a4c3d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_4207a68d-c93e-4097-93b8-88361e395789" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_c7a1ceb7-e039-450f-a18a-99c76a1a4c3d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesRevenueNetMember_7304657b-627e-4cd2-9cae-ac3620c42c78" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SalesRevenueNetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_c7a1ceb7-e039-450f-a18a-99c76a1a4c3d" xlink:to="loc_us-gaap_SalesRevenueNetMember_7304657b-627e-4cd2-9cae-ac3620c42c78" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_5a93be04-9dd6-4cc3-b75e-668751874c13" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MajorCustomersAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_edb54ae5-434a-4a73-abcc-0385cc5ccd42" xlink:to="loc_srt_MajorCustomersAxis_5a93be04-9dd6-4cc3-b75e-668751874c13" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_5a93be04-9dd6-4cc3-b75e-668751874c13_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_5a93be04-9dd6-4cc3-b75e-668751874c13" xlink:to="loc_srt_NameOfMajorCustomerDomain_5a93be04-9dd6-4cc3-b75e-668751874c13_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_23067a9d-cbd9-4c67-8efc-0dc4dd18cc34" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_5a93be04-9dd6-4cc3-b75e-668751874c13" xlink:to="loc_srt_NameOfMajorCustomerDomain_23067a9d-cbd9-4c67-8efc-0dc4dd18cc34" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_ExxonMobilCorporationMember_9b1d6599-c233-43e1-aab5-bc468269d41a" xlink:href="paa-20211231.xsd#paa_ExxonMobilCorporationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_23067a9d-cbd9-4c67-8efc-0dc4dd18cc34" xlink:to="loc_paa_ExxonMobilCorporationMember_9b1d6599-c233-43e1-aab5-bc468269d41a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_MarathonPetroleumCorporationMember_f2031445-d5db-4927-93fc-5a27b5b895f7" xlink:href="paa-20211231.xsd#paa_MarathonPetroleumCorporationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_23067a9d-cbd9-4c67-8efc-0dc4dd18cc34" xlink:to="loc_paa_MarathonPetroleumCorporationMember_f2031445-d5db-4927-93fc-5a27b5b895f7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_BPPlcAndSubsidiariesMember_75e1941f-b1f3-4829-a38f-be031c0f54a4" xlink:href="paa-20211231.xsd#paa_BPPlcAndSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_23067a9d-cbd9-4c67-8efc-0dc4dd18cc34" xlink:to="loc_paa_BPPlcAndSubsidiariesMember_75e1941f-b1f3-4829-a38f-be031c0f54a4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_Phillips66CompanyMember_3fc87761-aa08-4ecd-b1e9-2280d06b3a76" xlink:href="paa-20211231.xsd#paa_Phillips66CompanyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_23067a9d-cbd9-4c67-8efc-0dc4dd18cc34" xlink:to="loc_paa_Phillips66CompanyMember_3fc87761-aa08-4ecd-b1e9-2280d06b3a76" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_47b51235-726c-4dfe-8f20-0911d0ed20a4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_edb54ae5-434a-4a73-abcc-0385cc5ccd42" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_47b51235-726c-4dfe-8f20-0911d0ed20a4" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_47b51235-726c-4dfe-8f20-0911d0ed20a4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_47b51235-726c-4dfe-8f20-0911d0ed20a4" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_47b51235-726c-4dfe-8f20-0911d0ed20a4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_74dede59-58ec-46c3-a4f5-0160fe530bea" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_47b51235-726c-4dfe-8f20-0911d0ed20a4" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_74dede59-58ec-46c3-a4f5-0160fe530bea" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerConcentrationRiskMember_f9fc57ce-0db4-4cbb-94cc-b31f6af31af8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CustomerConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_74dede59-58ec-46c3-a4f5-0160fe530bea" xlink:to="loc_us-gaap_CustomerConcentrationRiskMember_f9fc57ce-0db4-4cbb-94cc-b31f6af31af8" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/RelatedPartyTransactionsDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#RelatedPartyTransactionsDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/RelatedPartyTransactionsDetails" xlink:type="extended" id="i60674fd432b64688a3f7d47da1705951_RelatedPartyTransactionsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_79f760ef-d223-455c-bc64-0070f9d4d714" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_LimitedLiabilityCompanyLLCorLimitedPartnershipLPMembersorLimitedPartnersOwnershipInterestUnits_68ad6aa3-49a4-4c30-8986-8937f5b31b2b" xlink:href="paa-20211231.xsd#paa_LimitedLiabilityCompanyLLCorLimitedPartnershipLPMembersorLimitedPartnersOwnershipInterestUnits"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_79f760ef-d223-455c-bc64-0070f9d4d714" xlink:to="loc_paa_LimitedLiabilityCompanyLLCorLimitedPartnershipLPMembersorLimitedPartnersOwnershipInterestUnits_68ad6aa3-49a4-4c30-8986-8937f5b31b2b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentForAdministrativeFees_d4c5e754-1a91-47e8-8465-af9c4c3211fc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentForAdministrativeFees"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_79f760ef-d223-455c-bc64-0070f9d4d714" xlink:to="loc_us-gaap_PaymentForAdministrativeFees_d4c5e754-1a91-47e8-8465-af9c4c3211fc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_ExpensesPaidOnBehalfOfAffiliate_5ab995a9-5acb-4d99-9a58-bd2a005c701f" xlink:href="paa-20211231.xsd#paa_ExpensesPaidOnBehalfOfAffiliate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_79f760ef-d223-455c-bc64-0070f9d4d714" xlink:to="loc_paa_ExpensesPaidOnBehalfOfAffiliate_5ab995a9-5acb-4d99-9a58-bd2a005c701f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPMembersOrLimitedPartnersOwnershipInterest_97725646-b560-4a80-b23f-cadbded2a807" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPMembersOrLimitedPartnersOwnershipInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_79f760ef-d223-455c-bc64-0070f9d4d714" xlink:to="loc_us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPMembersOrLimitedPartnersOwnershipInterest_97725646-b560-4a80-b23f-cadbded2a807" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromRelatedParties_baf664b3-8039-4a1b-ba69-efb9e0d1b77b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueFromRelatedParties"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_79f760ef-d223-455c-bc64-0070f9d4d714" xlink:to="loc_us-gaap_RevenueFromRelatedParties_baf664b3-8039-4a1b-ba69-efb9e0d1b77b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionPurchasesFromRelatedParty_e549914c-2361-4a6c-907d-2245d978a0f2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionPurchasesFromRelatedParty"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_79f760ef-d223-455c-bc64-0070f9d4d714" xlink:to="loc_us-gaap_RelatedPartyTransactionPurchasesFromRelatedParty_e549914c-2361-4a6c-907d-2245d978a0f2" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DueFromRelatedPartiesCurrent_c68385b0-9942-4483-bbd8-a27ca9f2f271" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DueFromRelatedPartiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_79f760ef-d223-455c-bc64-0070f9d4d714" xlink:to="loc_us-gaap_DueFromRelatedPartiesCurrent_c68385b0-9942-4483-bbd8-a27ca9f2f271" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DueToRelatedPartiesCurrent_316f3538-622e-4e9c-847e-f6757e0cdec8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DueToRelatedPartiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_79f760ef-d223-455c-bc64-0070f9d4d714" xlink:to="loc_us-gaap_DueToRelatedPartiesCurrent_316f3538-622e-4e9c-847e-f6757e0cdec8" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_660bd3c6-b812-4975-b852-ca2c6a7de86a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_79f760ef-d223-455c-bc64-0070f9d4d714" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_660bd3c6-b812-4975-b852-ca2c6a7de86a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipAxis_bfaa97ba-2f8f-4631-9b89-2096380f3d96" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_OwnershipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_660bd3c6-b812-4975-b852-ca2c6a7de86a" xlink:to="loc_srt_OwnershipAxis_bfaa97ba-2f8f-4631-9b89-2096380f3d96" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_bfaa97ba-2f8f-4631-9b89-2096380f3d96_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_OwnershipAxis_bfaa97ba-2f8f-4631-9b89-2096380f3d96" xlink:to="loc_srt_OwnershipDomain_bfaa97ba-2f8f-4631-9b89-2096380f3d96_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_d85c55b5-30d1-4c80-9756-7236487a5be0" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_OwnershipAxis_bfaa97ba-2f8f-4631-9b89-2096380f3d96" xlink:to="loc_srt_OwnershipDomain_d85c55b5-30d1-4c80-9756-7236487a5be0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PlainsGPHoldingsLPMember_3911018c-e40d-454a-b707-ed923f4cf305" xlink:href="paa-20211231.xsd#paa_PlainsGPHoldingsLPMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_OwnershipDomain_d85c55b5-30d1-4c80-9756-7236487a5be0" xlink:to="loc_paa_PlainsGPHoldingsLPMember_3911018c-e40d-454a-b707-ed923f4cf305" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PlainsAapLPMember_f3081253-7ddb-45cb-b5cb-6c5805cf91ab" xlink:href="paa-20211231.xsd#paa_PlainsAapLPMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_OwnershipDomain_d85c55b5-30d1-4c80-9756-7236487a5be0" xlink:to="loc_paa_PlainsAapLPMember_f3081253-7ddb-45cb-b5cb-6c5805cf91ab" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionAxis_fdcf873e-086e-4681-83e8-2d029a310a1a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_660bd3c6-b812-4975-b852-ca2c6a7de86a" xlink:to="loc_us-gaap_RelatedPartyTransactionAxis_fdcf873e-086e-4681-83e8-2d029a310a1a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_fdcf873e-086e-4681-83e8-2d029a310a1a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_fdcf873e-086e-4681-83e8-2d029a310a1a" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_fdcf873e-086e-4681-83e8-2d029a310a1a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_3430527b-70a0-422a-8526-4dd916b89796" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_fdcf873e-086e-4681-83e8-2d029a310a1a" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_3430527b-70a0-422a-8526-4dd916b89796" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_OmnibusAgreementMember_cb7dc1e3-d42b-47af-b7a8-263bfe0ecc15" xlink:href="paa-20211231.xsd#paa_OmnibusAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_3430527b-70a0-422a-8526-4dd916b89796" xlink:to="loc_paa_OmnibusAgreementMember_cb7dc1e3-d42b-47af-b7a8-263bfe0ecc15" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_20ec4900-fbc0-47fe-950e-5ac6cea403d6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountByClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_660bd3c6-b812-4975-b852-ca2c6a7de86a" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_20ec4900-fbc0-47fe-950e-5ac6cea403d6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_20ec4900-fbc0-47fe-950e-5ac6cea403d6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_20ec4900-fbc0-47fe-950e-5ac6cea403d6" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_20ec4900-fbc0-47fe-950e-5ac6cea403d6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_f3522e1c-0391-4ab7-a323-0982feb6d2b0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_20ec4900-fbc0-47fe-950e-5ac6cea403d6" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_f3522e1c-0391-4ab7-a323-0982feb6d2b0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SharesClassCMember_cff40663-808b-4fbd-b300-d08ed3e89782" xlink:href="paa-20211231.xsd#paa_SharesClassCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_f3522e1c-0391-4ab7-a323-0982feb6d2b0" xlink:to="loc_paa_SharesClassCMember_cff40663-808b-4fbd-b300-d08ed3e89782" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_9f8c58bc-58d4-472b-bdcc-4b1c87728b7f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_660bd3c6-b812-4975-b852-ca2c6a7de86a" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_9f8c58bc-58d4-472b-bdcc-4b1c87728b7f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_9f8c58bc-58d4-472b-bdcc-4b1c87728b7f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_9f8c58bc-58d4-472b-bdcc-4b1c87728b7f" xlink:to="loc_us-gaap_RelatedPartyDomain_9f8c58bc-58d4-472b-bdcc-4b1c87728b7f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_aba3475b-d40f-4827-8565-2c8b36793545" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_9f8c58bc-58d4-472b-bdcc-4b1c87728b7f" xlink:to="loc_us-gaap_RelatedPartyDomain_aba3475b-d40f-4827-8565-2c8b36793545" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PlainsGPHoldingsLPMember_bb5c4165-0fa5-4189-90e7-eecf436407ba" xlink:href="paa-20211231.xsd#paa_PlainsGPHoldingsLPMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_aba3475b-d40f-4827-8565-2c8b36793545" xlink:to="loc_paa_PlainsGPHoldingsLPMember_bb5c4165-0fa5-4189-90e7-eecf436407ba" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralPartnerMember_420422e8-5733-491e-9bbf-8c87037b8d1f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GeneralPartnerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_aba3475b-d40f-4827-8565-2c8b36793545" xlink:to="loc_us-gaap_GeneralPartnerMember_420422e8-5733-491e-9bbf-8c87037b8d1f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PlainsAapLPMember_eea39b34-6ba1-4965-bbd9-54d4d20facc5" xlink:href="paa-20211231.xsd#paa_PlainsAapLPMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_aba3475b-d40f-4827-8565-2c8b36793545" xlink:to="loc_paa_PlainsAapLPMember_eea39b34-6ba1-4965-bbd9-54d4d20facc5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PrincipalOwnerMember_602ef1cd-04da-49bd-b5ac-447b5bbaeb39" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PrincipalOwnerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_aba3475b-d40f-4827-8565-2c8b36793545" xlink:to="loc_us-gaap_PrincipalOwnerMember_602ef1cd-04da-49bd-b5ac-447b5bbaeb39" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_d705dbe2-2d12-46bb-b86f-63959a593042" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_660bd3c6-b812-4975-b852-ca2c6a7de86a" xlink:to="loc_srt_RangeAxis_d705dbe2-2d12-46bb-b86f-63959a593042" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_d705dbe2-2d12-46bb-b86f-63959a593042_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_d705dbe2-2d12-46bb-b86f-63959a593042" xlink:to="loc_srt_RangeMember_d705dbe2-2d12-46bb-b86f-63959a593042_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_0c20a776-76f7-42a2-9aec-e49e7439ee96" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_d705dbe2-2d12-46bb-b86f-63959a593042" xlink:to="loc_srt_RangeMember_0c20a776-76f7-42a2-9aec-e49e7439ee96" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_614e6b19-06fd-4f0d-bc0c-682a08b0dbac" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_0c20a776-76f7-42a2-9aec-e49e7439ee96" xlink:to="loc_srt_MinimumMember_614e6b19-06fd-4f0d-bc0c-682a08b0dbac" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/EquityIndexedCompensationPlansPlanInformationDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#EquityIndexedCompensationPlansPlanInformationDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/EquityIndexedCompensationPlansPlanInformationDetails" xlink:type="extended" id="i450eb67d065645e4b3382190d2a0a500_EquityIndexedCompensationPlansPlanInformationDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_9e1884f6-966f-4dff-8d73-ae8eea4f26f4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_63b86b1c-5ccc-4476-986d-449b2d9387eb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_9e1884f6-966f-4dff-8d73-ae8eea4f26f4" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_63b86b1c-5ccc-4476-986d-449b2d9387eb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_786c9c6b-3c1e-4a88-9cb9-21f86e43ab72" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_9e1884f6-966f-4dff-8d73-ae8eea4f26f4" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_786c9c6b-3c1e-4a88-9cb9-21f86e43ab72" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_245a73c4-47d0-4153-9d6a-4169322a69a6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_9e1884f6-966f-4dff-8d73-ae8eea4f26f4" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_245a73c4-47d0-4153-9d6a-4169322a69a6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsIncludingDistributionEquivalentRightsOutstanding_ee9793c9-87a0-431c-96f8-ded39f7b01f4" xlink:href="paa-20211231.xsd#paa_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsIncludingDistributionEquivalentRightsOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_9e1884f6-966f-4dff-8d73-ae8eea4f26f4" xlink:to="loc_paa_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsIncludingDistributionEquivalentRightsOutstanding_ee9793c9-87a0-431c-96f8-ded39f7b01f4" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsProbableVestingUnrecognizedFairValue_bf2d0ce0-ea2b-4396-92a6-e2e10635142f" xlink:href="paa-20211231.xsd#paa_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsProbableVestingUnrecognizedFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_9e1884f6-966f-4dff-8d73-ae8eea4f26f4" xlink:to="loc_paa_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsProbableVestingUnrecognizedFairValue_bf2d0ce0-ea2b-4396-92a6-e2e10635142f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_899e987e-343f-4db6-8191-4c799d910a43" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_9e1884f6-966f-4dff-8d73-ae8eea4f26f4" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_899e987e-343f-4db6-8191-4c799d910a43" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_b47be1b6-1f50-4a6f-b2ba-355f38d0a2c7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PlanNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_899e987e-343f-4db6-8191-4c799d910a43" xlink:to="loc_us-gaap_PlanNameAxis_b47be1b6-1f50-4a6f-b2ba-355f38d0a2c7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_b47be1b6-1f50-4a6f-b2ba-355f38d0a2c7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_b47be1b6-1f50-4a6f-b2ba-355f38d0a2c7" xlink:to="loc_us-gaap_PlanNameDomain_b47be1b6-1f50-4a6f-b2ba-355f38d0a2c7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_5b406417-e3c9-446b-a87d-9aabc79b1db7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_b47be1b6-1f50-4a6f-b2ba-355f38d0a2c7" xlink:to="loc_us-gaap_PlanNameDomain_5b406417-e3c9-446b-a87d-9aabc79b1db7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PlainsAllAmerican2017LongTermIncentivePlanMember_cea756f2-a15f-44c7-8785-39999ab59925" xlink:href="paa-20211231.xsd#paa_PlainsAllAmerican2017LongTermIncentivePlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_5b406417-e3c9-446b-a87d-9aabc79b1db7" xlink:to="loc_paa_PlainsAllAmerican2017LongTermIncentivePlanMember_cea756f2-a15f-44c7-8785-39999ab59925" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PlainsAllAmericanPNGSuccessorLongTermIncentivePlanMember_f6ba5328-cab9-48db-b650-a1a96836d7d5" xlink:href="paa-20211231.xsd#paa_PlainsAllAmericanPNGSuccessorLongTermIncentivePlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_5b406417-e3c9-446b-a87d-9aabc79b1db7" xlink:to="loc_paa_PlainsAllAmericanPNGSuccessorLongTermIncentivePlanMember_f6ba5328-cab9-48db-b650-a1a96836d7d5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_PlainsAllAmericanGPLLCLongTermIncentiveTrackingUnitPlanMember_6a4f12e7-9be7-40a9-a34a-c8e61c7bb94d" xlink:href="paa-20211231.xsd#paa_PlainsAllAmericanGPLLCLongTermIncentiveTrackingUnitPlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_5b406417-e3c9-446b-a87d-9aabc79b1db7" xlink:to="loc_paa_PlainsAllAmericanGPLLCLongTermIncentiveTrackingUnitPlanMember_6a4f12e7-9be7-40a9-a34a-c8e61c7bb94d" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/CommitmentsandContingenciesCommitmentsDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#CommitmentsandContingenciesCommitmentsDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/CommitmentsandContingenciesCommitmentsDetails" xlink:type="extended" id="i313413a945ee4f518f1537bf3178e8bb_CommitmentsandContingenciesCommitmentsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsLineItems_3cc02b57-3053-4c68-8acf-a8dd0d3f3e53" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherCommitmentsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeasesAbstract_5c19aff6-9835-4f07-9c17-6d1e3a33de40" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LeasesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_3cc02b57-3053-4c68-8acf-a8dd0d3f3e53" xlink:to="loc_us-gaap_LeasesAbstract_5c19aff6-9835-4f07-9c17-6d1e3a33de40" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_LeasesFutureMinimumPaymentsDueInOneYear_434ae45d-cd3d-4c35-81e6-e55371e4964e" xlink:href="paa-20211231.xsd#paa_LeasesFutureMinimumPaymentsDueInOneYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LeasesAbstract_5c19aff6-9835-4f07-9c17-6d1e3a33de40" xlink:to="loc_paa_LeasesFutureMinimumPaymentsDueInOneYear_434ae45d-cd3d-4c35-81e6-e55371e4964e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_LeasesFutureMinimumPaymentsDueInTwoYears_a311f8f2-02be-4616-9f6c-57ecc2bf3616" xlink:href="paa-20211231.xsd#paa_LeasesFutureMinimumPaymentsDueInTwoYears"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LeasesAbstract_5c19aff6-9835-4f07-9c17-6d1e3a33de40" xlink:to="loc_paa_LeasesFutureMinimumPaymentsDueInTwoYears_a311f8f2-02be-4616-9f6c-57ecc2bf3616" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_LeasesFutureMinimumPaymentsDueInThreeYear_5c609a2e-ceb9-436a-b7e1-88e54ad32681" xlink:href="paa-20211231.xsd#paa_LeasesFutureMinimumPaymentsDueInThreeYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LeasesAbstract_5c19aff6-9835-4f07-9c17-6d1e3a33de40" xlink:to="loc_paa_LeasesFutureMinimumPaymentsDueInThreeYear_5c609a2e-ceb9-436a-b7e1-88e54ad32681" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_LeasesFutureMinimumPaymentsDueInFourYears_72b59720-21a8-417b-aabe-3bd4335a43d5" xlink:href="paa-20211231.xsd#paa_LeasesFutureMinimumPaymentsDueInFourYears"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LeasesAbstract_5c19aff6-9835-4f07-9c17-6d1e3a33de40" xlink:to="loc_paa_LeasesFutureMinimumPaymentsDueInFourYears_72b59720-21a8-417b-aabe-3bd4335a43d5" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_LeasesFutureMinimumPaymentsDueInFiveYears_c9c3a4b5-6b13-4cee-8bcb-8f8de65ec7e9" xlink:href="paa-20211231.xsd#paa_LeasesFutureMinimumPaymentsDueInFiveYears"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LeasesAbstract_5c19aff6-9835-4f07-9c17-6d1e3a33de40" xlink:to="loc_paa_LeasesFutureMinimumPaymentsDueInFiveYears_c9c3a4b5-6b13-4cee-8bcb-8f8de65ec7e9" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_LeasesFutureMinimumPaymentsDueThereafter_c8cde9c1-4c23-4126-b98e-cd307b24ec40" xlink:href="paa-20211231.xsd#paa_LeasesFutureMinimumPaymentsDueThereafter"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LeasesAbstract_5c19aff6-9835-4f07-9c17-6d1e3a33de40" xlink:to="loc_paa_LeasesFutureMinimumPaymentsDueThereafter_c8cde9c1-4c23-4126-b98e-cd307b24ec40" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_LeasesFutureMinimumPaymentsDue_7b486ae7-6979-4cd2-8477-97420f4f55e9" xlink:href="paa-20211231.xsd#paa_LeasesFutureMinimumPaymentsDue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LeasesAbstract_5c19aff6-9835-4f07-9c17-6d1e3a33de40" xlink:to="loc_paa_LeasesFutureMinimumPaymentsDue_7b486ae7-6979-4cd2-8477-97420f4f55e9" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentFiscalYearMaturityAbstract_3115e742-821c-437c-b47c-6a8cd475c24d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherCommitmentFiscalYearMaturityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_3cc02b57-3053-4c68-8acf-a8dd0d3f3e53" xlink:to="loc_us-gaap_OtherCommitmentFiscalYearMaturityAbstract_3115e742-821c-437c-b47c-6a8cd475c24d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentDueInNextTwelveMonths_9683728f-e4be-4d9f-979d-0b5fe8c2c32e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherCommitmentDueInNextTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentFiscalYearMaturityAbstract_3115e742-821c-437c-b47c-6a8cd475c24d" xlink:to="loc_us-gaap_OtherCommitmentDueInNextTwelveMonths_9683728f-e4be-4d9f-979d-0b5fe8c2c32e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentDueInSecondYear_c646d54c-2e6b-46bb-b7d0-02e163ba064d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherCommitmentDueInSecondYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentFiscalYearMaturityAbstract_3115e742-821c-437c-b47c-6a8cd475c24d" xlink:to="loc_us-gaap_OtherCommitmentDueInSecondYear_c646d54c-2e6b-46bb-b7d0-02e163ba064d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentDueInThirdYear_812dc11d-de47-41b4-a476-fa82c7838330" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherCommitmentDueInThirdYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentFiscalYearMaturityAbstract_3115e742-821c-437c-b47c-6a8cd475c24d" xlink:to="loc_us-gaap_OtherCommitmentDueInThirdYear_812dc11d-de47-41b4-a476-fa82c7838330" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentDueInFourthYear_a565b5bc-b139-40c4-811e-be482da12ee2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherCommitmentDueInFourthYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentFiscalYearMaturityAbstract_3115e742-821c-437c-b47c-6a8cd475c24d" xlink:to="loc_us-gaap_OtherCommitmentDueInFourthYear_a565b5bc-b139-40c4-811e-be482da12ee2" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentDueInFifthYear_77ff90b4-ef1a-4930-96d0-a1484b147ad9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherCommitmentDueInFifthYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentFiscalYearMaturityAbstract_3115e742-821c-437c-b47c-6a8cd475c24d" xlink:to="loc_us-gaap_OtherCommitmentDueInFifthYear_77ff90b4-ef1a-4930-96d0-a1484b147ad9" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentDueAfterFifthYear_ceaa5822-c42b-4f98-a9cb-db7b4fde8bc6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherCommitmentDueAfterFifthYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentFiscalYearMaturityAbstract_3115e742-821c-437c-b47c-6a8cd475c24d" xlink:to="loc_us-gaap_OtherCommitmentDueAfterFifthYear_ceaa5822-c42b-4f98-a9cb-db7b4fde8bc6" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitment_752a2cf7-071b-46c5-bd32-36efdd8512b6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherCommitment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentFiscalYearMaturityAbstract_3115e742-821c-437c-b47c-6a8cd475c24d" xlink:to="loc_us-gaap_OtherCommitment_752a2cf7-071b-46c5-bd32-36efdd8512b6" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractualObligationFiscalYearMaturityScheduleAbstract_47f2a7b7-d8ef-4a37-a3c6-c7d862725130" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractualObligationFiscalYearMaturityScheduleAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_3cc02b57-3053-4c68-8acf-a8dd0d3f3e53" xlink:to="loc_us-gaap_ContractualObligationFiscalYearMaturityScheduleAbstract_47f2a7b7-d8ef-4a37-a3c6-c7d862725130" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractualObligationDueInNextTwelveMonths_5ea0cabd-bd5a-417b-9767-93dfb9643f73" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractualObligationDueInNextTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractualObligationFiscalYearMaturityScheduleAbstract_47f2a7b7-d8ef-4a37-a3c6-c7d862725130" xlink:to="loc_us-gaap_ContractualObligationDueInNextTwelveMonths_5ea0cabd-bd5a-417b-9767-93dfb9643f73" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractualObligationDueInSecondYear_5506f79a-993f-4a28-b587-9e32e2492044" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractualObligationDueInSecondYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractualObligationFiscalYearMaturityScheduleAbstract_47f2a7b7-d8ef-4a37-a3c6-c7d862725130" xlink:to="loc_us-gaap_ContractualObligationDueInSecondYear_5506f79a-993f-4a28-b587-9e32e2492044" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractualObligationDueInThirdYear_a13938ec-000a-487f-a4ec-b1ac34775919" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractualObligationDueInThirdYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractualObligationFiscalYearMaturityScheduleAbstract_47f2a7b7-d8ef-4a37-a3c6-c7d862725130" xlink:to="loc_us-gaap_ContractualObligationDueInThirdYear_a13938ec-000a-487f-a4ec-b1ac34775919" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractualObligationDueInFourthYear_8a9b3d42-1d3a-468b-a43d-fcb0035ee7da" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractualObligationDueInFourthYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractualObligationFiscalYearMaturityScheduleAbstract_47f2a7b7-d8ef-4a37-a3c6-c7d862725130" xlink:to="loc_us-gaap_ContractualObligationDueInFourthYear_8a9b3d42-1d3a-468b-a43d-fcb0035ee7da" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractualObligationDueInFifthYear_8c569e3a-0e12-4bb1-a8f2-9883b0d8f480" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractualObligationDueInFifthYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractualObligationFiscalYearMaturityScheduleAbstract_47f2a7b7-d8ef-4a37-a3c6-c7d862725130" xlink:to="loc_us-gaap_ContractualObligationDueInFifthYear_8c569e3a-0e12-4bb1-a8f2-9883b0d8f480" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractualObligationDueAfterFifthYear_721b0efc-9a55-49a5-bfa3-2bf96dbb2235" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractualObligationDueAfterFifthYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractualObligationFiscalYearMaturityScheduleAbstract_47f2a7b7-d8ef-4a37-a3c6-c7d862725130" xlink:to="loc_us-gaap_ContractualObligationDueAfterFifthYear_721b0efc-9a55-49a5-bfa3-2bf96dbb2235" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractualObligation_b7a15a12-986a-42ea-aa51-90a6f2214327" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractualObligation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractualObligationFiscalYearMaturityScheduleAbstract_47f2a7b7-d8ef-4a37-a3c6-c7d862725130" xlink:to="loc_us-gaap_ContractualObligation_b7a15a12-986a-42ea-aa51-90a6f2214327" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnrecordedUnconditionalPurchaseObligationPurchases_002d2a81-18be-43fc-a2bc-ac32ad294cd1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnrecordedUnconditionalPurchaseObligationPurchases"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_3cc02b57-3053-4c68-8acf-a8dd0d3f3e53" xlink:to="loc_us-gaap_UnrecordedUnconditionalPurchaseObligationPurchases_002d2a81-18be-43fc-a2bc-ac32ad294cd1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_8d73a254-cb93-47d5-9045-f49b96771ffd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_3cc02b57-3053-4c68-8acf-a8dd0d3f3e53" xlink:to="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_8d73a254-cb93-47d5-9045-f49b96771ffd" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsTable_25642dbc-68aa-4785-8018-70875b9f9bb9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherCommitmentsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_3cc02b57-3053-4c68-8acf-a8dd0d3f3e53" xlink:to="loc_us-gaap_OtherCommitmentsTable_25642dbc-68aa-4785-8018-70875b9f9bb9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsAxis_8ae075a0-3fda-452d-9e55-6e6e343f9997" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherCommitmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_OtherCommitmentsTable_25642dbc-68aa-4785-8018-70875b9f9bb9" xlink:to="loc_us-gaap_OtherCommitmentsAxis_8ae075a0-3fda-452d-9e55-6e6e343f9997" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsDomain_8ae075a0-3fda-452d-9e55-6e6e343f9997_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherCommitmentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_OtherCommitmentsAxis_8ae075a0-3fda-452d-9e55-6e6e343f9997" xlink:to="loc_us-gaap_OtherCommitmentsDomain_8ae075a0-3fda-452d-9e55-6e6e343f9997_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsDomain_f71a7142-0a84-4ff5-adaa-c511c1c8d14d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherCommitmentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_OtherCommitmentsAxis_8ae075a0-3fda-452d-9e55-6e6e343f9997" xlink:to="loc_us-gaap_OtherCommitmentsDomain_f71a7142-0a84-4ff5-adaa-c511c1c8d14d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_AgreementsToUtilizeAssetsOfEquityMethodInvesteesMember_c81789c7-405c-4f0a-8cdd-ecef912be4ee" xlink:href="paa-20211231.xsd#paa_AgreementsToUtilizeAssetsOfEquityMethodInvesteesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsDomain_f71a7142-0a84-4ff5-adaa-c511c1c8d14d" xlink:to="loc_paa_AgreementsToUtilizeAssetsOfEquityMethodInvesteesMember_c81789c7-405c-4f0a-8cdd-ecef912be4ee" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_518323cc-c5cf-4cf0-9708-d415c9f30f05" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_OtherCommitmentsTable_25642dbc-68aa-4785-8018-70875b9f9bb9" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_518323cc-c5cf-4cf0-9708-d415c9f30f05" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_518323cc-c5cf-4cf0-9708-d415c9f30f05_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_518323cc-c5cf-4cf0-9708-d415c9f30f05" xlink:to="loc_us-gaap_RelatedPartyDomain_518323cc-c5cf-4cf0-9708-d415c9f30f05_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_484831c7-4b6f-4f92-8c6b-38635beb4a87" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_518323cc-c5cf-4cf0-9708-d415c9f30f05" xlink:to="loc_us-gaap_RelatedPartyDomain_484831c7-4b6f-4f92-8c6b-38635beb4a87" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvesteeMember_c57cca82-af1c-4af8-b4e9-a61eb510ecbc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityMethodInvesteeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_484831c7-4b6f-4f92-8c6b-38635beb4a87" xlink:to="loc_us-gaap_EquityMethodInvesteeMember_c57cca82-af1c-4af8-b4e9-a61eb510ecbc" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/CommitmentsandContingenciesLegalEnvironmentalorRegulatoryDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#CommitmentsandContingenciesLegalEnvironmentalorRegulatoryDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/CommitmentsandContingenciesLegalEnvironmentalorRegulatoryDetails" xlink:type="extended" id="i581213d410c946b8bdf142dd5efc1a7a_CommitmentsandContingenciesLegalEnvironmentalorRegulatoryDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesLineItems_c0c9bd95-1c5e-4285-b7f3-d45b95ec81f9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LossContingenciesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccrualForEnvironmentalLossContingenciesGross_ec88e400-eb53-4b7a-af4d-623111d462c8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccrualForEnvironmentalLossContingenciesGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_c0c9bd95-1c5e-4285-b7f3-d45b95ec81f9" xlink:to="loc_us-gaap_AccrualForEnvironmentalLossContingenciesGross_ec88e400-eb53-4b7a-af4d-623111d462c8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedEnvironmentalLossContingenciesCurrent_27fa1222-c178-45f7-b5cc-e5ebb8bf886d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccruedEnvironmentalLossContingenciesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_c0c9bd95-1c5e-4285-b7f3-d45b95ec81f9" xlink:to="loc_us-gaap_AccruedEnvironmentalLossContingenciesCurrent_27fa1222-c178-45f7-b5cc-e5ebb8bf886d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedEnvironmentalLossContingenciesNoncurrent_5baf35e7-9121-4350-a441-c42de69bd3e3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccruedEnvironmentalLossContingenciesNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_c0c9bd95-1c5e-4285-b7f3-d45b95ec81f9" xlink:to="loc_us-gaap_AccruedEnvironmentalLossContingenciesNoncurrent_5baf35e7-9121-4350-a441-c42de69bd3e3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RecordedThirdPartyEnvironmentalRecoveriesReceivable_054099a2-184f-4cbc-bcb0-9b5bb95b21ec" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RecordedThirdPartyEnvironmentalRecoveriesReceivable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_c0c9bd95-1c5e-4285-b7f3-d45b95ec81f9" xlink:to="loc_us-gaap_RecordedThirdPartyEnvironmentalRecoveriesReceivable_054099a2-184f-4cbc-bcb0-9b5bb95b21ec" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_EstimatedSizeOfRelease_80fddc8c-422d-47b9-8e53-b9e6d34b1a08" xlink:href="paa-20211231.xsd#paa_EstimatedSizeOfRelease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_c0c9bd95-1c5e-4285-b7f3-d45b95ec81f9" xlink:to="loc_paa_EstimatedSizeOfRelease_80fddc8c-422d-47b9-8e53-b9e6d34b1a08" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_EstimatedSizeOfReleaseToReachBodyOfWater_56256685-6645-4cf7-ad2e-75f3e8d986b8" xlink:href="paa-20211231.xsd#paa_EstimatedSizeOfReleaseToReachBodyOfWater"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_c0c9bd95-1c5e-4285-b7f3-d45b95ec81f9" xlink:to="loc_paa_EstimatedSizeOfReleaseToReachBodyOfWater_56256685-6645-4cf7-ad2e-75f3e8d986b8" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyDamagesPaidValue_6b936912-87b0-405b-b936-2e57f27e9d07" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LossContingencyDamagesPaidValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_c0c9bd95-1c5e-4285-b7f3-d45b95ec81f9" xlink:to="loc_us-gaap_LossContingencyDamagesPaidValue_6b936912-87b0-405b-b936-2e57f27e9d07" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_IndictmentNumberofFelonyChargesGuiltyVerdict_c597765e-1171-4c5c-8744-3c61ceb84498" xlink:href="paa-20211231.xsd#paa_IndictmentNumberofFelonyChargesGuiltyVerdict"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_c0c9bd95-1c5e-4285-b7f3-d45b95ec81f9" xlink:to="loc_paa_IndictmentNumberofFelonyChargesGuiltyVerdict_c597765e-1171-4c5c-8744-3c61ceb84498" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_IndictmentNumberofMisdemeanorChargesGuiltyVerdict_f8054bcd-b2e6-459b-9093-4011b7996424" xlink:href="paa-20211231.xsd#paa_IndictmentNumberofMisdemeanorChargesGuiltyVerdict"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_c0c9bd95-1c5e-4285-b7f3-d45b95ec81f9" xlink:to="loc_paa_IndictmentNumberofMisdemeanorChargesGuiltyVerdict_f8054bcd-b2e6-459b-9093-4011b7996424" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_IndictmentNumberofMisdemeanorChargesGuiltyVerdictReportingCount_f91368cb-1ced-4da0-8899-10468bf34fe8" xlink:href="paa-20211231.xsd#paa_IndictmentNumberofMisdemeanorChargesGuiltyVerdictReportingCount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_c0c9bd95-1c5e-4285-b7f3-d45b95ec81f9" xlink:to="loc_paa_IndictmentNumberofMisdemeanorChargesGuiltyVerdictReportingCount_f91368cb-1ced-4da0-8899-10468bf34fe8" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_IndictmentNumberofMisdemeanorChargesGuiltyVerdictStrictLiabilityDischargeCount_3403cad3-97e8-4e9d-ae39-a1c03809c92a" xlink:href="paa-20211231.xsd#paa_IndictmentNumberofMisdemeanorChargesGuiltyVerdictStrictLiabilityDischargeCount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_c0c9bd95-1c5e-4285-b7f3-d45b95ec81f9" xlink:to="loc_paa_IndictmentNumberofMisdemeanorChargesGuiltyVerdictStrictLiabilityDischargeCount_3403cad3-97e8-4e9d-ae39-a1c03809c92a" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_IndictmentNumberofMisdemeanorChargesGuiltyVerdictStrictLiabilityAnimalTakingsCount_a5549fa3-f8eb-477b-b994-28e754ca5770" xlink:href="paa-20211231.xsd#paa_IndictmentNumberofMisdemeanorChargesGuiltyVerdictStrictLiabilityAnimalTakingsCount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_c0c9bd95-1c5e-4285-b7f3-d45b95ec81f9" xlink:to="loc_paa_IndictmentNumberofMisdemeanorChargesGuiltyVerdictStrictLiabilityAnimalTakingsCount_a5549fa3-f8eb-477b-b994-28e754ca5770" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_IndictmentNumberofMisdemeanorChargesNotGuiltyVerdictStrictLiabilityAnimalTakingsCount_d71721ef-a723-4f10-8bf2-1c5ef6a5892e" xlink:href="paa-20211231.xsd#paa_IndictmentNumberofMisdemeanorChargesNotGuiltyVerdictStrictLiabilityAnimalTakingsCount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_c0c9bd95-1c5e-4285-b7f3-d45b95ec81f9" xlink:to="loc_paa_IndictmentNumberofMisdemeanorChargesNotGuiltyVerdictStrictLiabilityAnimalTakingsCount_d71721ef-a723-4f10-8bf2-1c5ef6a5892e" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_LossContingencyPenaltyOrFineAssessed_a18210f1-d889-479f-a829-34d586f74d49" xlink:href="paa-20211231.xsd#paa_LossContingencyPenaltyOrFineAssessed"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_c0c9bd95-1c5e-4285-b7f3-d45b95ec81f9" xlink:to="loc_paa_LossContingencyPenaltyOrFineAssessed_a18210f1-d889-479f-a829-34d586f74d49" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyDamagesAwardedValue_7e79d9b3-5980-485c-a4b7-6d43f829fc34" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LossContingencyDamagesAwardedValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_c0c9bd95-1c5e-4285-b7f3-d45b95ec81f9" xlink:to="loc_us-gaap_LossContingencyDamagesAwardedValue_7e79d9b3-5980-485c-a4b7-6d43f829fc34" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyNewClaimsFiledNumber_1be2cda8-63b9-497d-8d4f-92bd1c4e0865" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LossContingencyNewClaimsFiledNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_c0c9bd95-1c5e-4285-b7f3-d45b95ec81f9" xlink:to="loc_us-gaap_LossContingencyNewClaimsFiledNumber_1be2cda8-63b9-497d-8d4f-92bd1c4e0865" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyEstimateOfPossibleLoss_324682ab-d3dc-46f2-be56-036e57dbccb9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LossContingencyEstimateOfPossibleLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_c0c9bd95-1c5e-4285-b7f3-d45b95ec81f9" xlink:to="loc_us-gaap_LossContingencyEstimateOfPossibleLoss_324682ab-d3dc-46f2-be56-036e57dbccb9" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyReceivableProceeds_e7d2c9e1-3e66-4332-a466-bcea8bca7f56" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LossContingencyReceivableProceeds"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_c0c9bd95-1c5e-4285-b7f3-d45b95ec81f9" xlink:to="loc_us-gaap_LossContingencyReceivableProceeds_e7d2c9e1-3e66-4332-a466-bcea8bca7f56" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_ThirdPartyEnvironmentalRecoveriesReceivedAndReceivable_b20b7074-1d60-4c0c-84a9-49aced50e00a" xlink:href="paa-20211231.xsd#paa_ThirdPartyEnvironmentalRecoveriesReceivedAndReceivable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_c0c9bd95-1c5e-4285-b7f3-d45b95ec81f9" xlink:to="loc_paa_ThirdPartyEnvironmentalRecoveriesReceivedAndReceivable_b20b7074-1d60-4c0c-84a9-49aced50e00a" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesTable_5bbf7ab6-d077-40dc-ae14-a4319474af4d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LossContingenciesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LossContingenciesLineItems_c0c9bd95-1c5e-4285-b7f3-d45b95ec81f9" xlink:to="loc_us-gaap_LossContingenciesTable_5bbf7ab6-d077-40dc-ae14-a4319474af4d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_a455622a-7a22-4fa8-be7e-3db0e4f3099e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LossContingenciesByNatureOfContingencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_5bbf7ab6-d077-40dc-ae14-a4319474af4d" xlink:to="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_a455622a-7a22-4fa8-be7e-3db0e4f3099e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyNatureDomain_a455622a-7a22-4fa8-be7e-3db0e4f3099e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LossContingencyNatureDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_a455622a-7a22-4fa8-be7e-3db0e4f3099e" xlink:to="loc_us-gaap_LossContingencyNatureDomain_a455622a-7a22-4fa8-be7e-3db0e4f3099e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyNatureDomain_76cf1aeb-de6c-4f00-be08-7957557bf5cf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LossContingencyNatureDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_a455622a-7a22-4fa8-be7e-3db0e4f3099e" xlink:to="loc_us-gaap_LossContingencyNatureDomain_76cf1aeb-de6c-4f00-be08-7957557bf5cf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_Line901IncidentMember_6a56dfda-3677-4c03-bf72-e93c404ac89d" xlink:href="paa-20211231.xsd#paa_Line901IncidentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingencyNatureDomain_76cf1aeb-de6c-4f00-be08-7957557bf5cf" xlink:to="loc_paa_Line901IncidentMember_6a56dfda-3677-4c03-bf72-e93c404ac89d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseAxis_ff12642d-41ac-4ae7-844f-5832bc871aae" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_LitigationCaseAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_5bbf7ab6-d077-40dc-ae14-a4319474af4d" xlink:to="loc_srt_LitigationCaseAxis_ff12642d-41ac-4ae7-844f-5832bc871aae" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseTypeDomain_ff12642d-41ac-4ae7-844f-5832bc871aae_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_LitigationCaseTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_LitigationCaseAxis_ff12642d-41ac-4ae7-844f-5832bc871aae" xlink:to="loc_srt_LitigationCaseTypeDomain_ff12642d-41ac-4ae7-844f-5832bc871aae_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseTypeDomain_fe2ff772-0beb-4e67-b797-eb9ab3176ad8" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_LitigationCaseTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_LitigationCaseAxis_ff12642d-41ac-4ae7-844f-5832bc871aae" xlink:to="loc_srt_LitigationCaseTypeDomain_fe2ff772-0beb-4e67-b797-eb9ab3176ad8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_ConsentDecreeCivilPenaltiesMember_56b77b42-d09f-4102-99a6-46ce6db5cd5d" xlink:href="paa-20211231.xsd#paa_ConsentDecreeCivilPenaltiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_LitigationCaseTypeDomain_fe2ff772-0beb-4e67-b797-eb9ab3176ad8" xlink:to="loc_paa_ConsentDecreeCivilPenaltiesMember_56b77b42-d09f-4102-99a6-46ce6db5cd5d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_ConsentDecreeCompensationForInjuriesToDestructionOfLossOfUseOfNaturalResourcesMember_ddd0fa07-53d3-4360-b197-fb6658ba9de0" xlink:href="paa-20211231.xsd#paa_ConsentDecreeCompensationForInjuriesToDestructionOfLossOfUseOfNaturalResourcesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_LitigationCaseTypeDomain_fe2ff772-0beb-4e67-b797-eb9ab3176ad8" xlink:to="loc_paa_ConsentDecreeCompensationForInjuriesToDestructionOfLossOfUseOfNaturalResourcesMember_ddd0fa07-53d3-4360-b197-fb6658ba9de0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_IndictmentInCaliforniaSuperiorCourtSantaBarbaraCountyMember_d3e4ef7e-8246-4869-ab43-b70cb98b86ef" xlink:href="paa-20211231.xsd#paa_IndictmentInCaliforniaSuperiorCourtSantaBarbaraCountyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_LitigationCaseTypeDomain_fe2ff772-0beb-4e67-b797-eb9ab3176ad8" xlink:to="loc_paa_IndictmentInCaliforniaSuperiorCourtSantaBarbaraCountyMember_d3e4ef7e-8246-4869-ab43-b70cb98b86ef" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_ClassActionLawsuitsMember_8eb8d89a-e534-480c-9000-c917d381097a" xlink:href="paa-20211231.xsd#paa_ClassActionLawsuitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_LitigationCaseTypeDomain_fe2ff772-0beb-4e67-b797-eb9ab3176ad8" xlink:to="loc_paa_ClassActionLawsuitsMember_8eb8d89a-e534-480c-9000-c917d381097a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_UnitholderDerivativeLawsuitsMember_acedb69b-9bb8-4261-a2c1-6f1886189454" xlink:href="paa-20211231.xsd#paa_UnitholderDerivativeLawsuitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_LitigationCaseTypeDomain_fe2ff772-0beb-4e67-b797-eb9ab3176ad8" xlink:to="loc_paa_UnitholderDerivativeLawsuitsMember_acedb69b-9bb8-4261-a2c1-6f1886189454" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_1704ae25-7b81-40e7-9527-db011c4786eb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_5bbf7ab6-d077-40dc-ae14-a4319474af4d" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_1704ae25-7b81-40e7-9527-db011c4786eb" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_1704ae25-7b81-40e7-9527-db011c4786eb_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_1704ae25-7b81-40e7-9527-db011c4786eb" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_1704ae25-7b81-40e7-9527-db011c4786eb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_3491d50e-d091-4ca6-890a-33c04fd00d59" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_1704ae25-7b81-40e7-9527-db011c4786eb" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_3491d50e-d091-4ca6-890a-33c04fd00d59" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNoncurrentLiabilitiesMember_845dc325-b3e6-49e9-ba35-b4b9afcd7aa5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherNoncurrentLiabilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_3491d50e-d091-4ca6-890a-33c04fd00d59" xlink:to="loc_us-gaap_OtherNoncurrentLiabilitiesMember_845dc325-b3e6-49e9-ba35-b4b9afcd7aa5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNoncurrentAssetsMember_ee0aa27b-2bff-431f-b5b3-c0b025941a1b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherNoncurrentAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_3491d50e-d091-4ca6-890a-33c04fd00d59" xlink:to="loc_us-gaap_OtherNoncurrentAssetsMember_ee0aa27b-2bff-431f-b5b3-c0b025941a1b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_380742db-dbf8-4b30-a281-35fa2a47e717" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_5bbf7ab6-d077-40dc-ae14-a4319474af4d" xlink:to="loc_srt_RangeAxis_380742db-dbf8-4b30-a281-35fa2a47e717" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_380742db-dbf8-4b30-a281-35fa2a47e717_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_380742db-dbf8-4b30-a281-35fa2a47e717" xlink:to="loc_srt_RangeMember_380742db-dbf8-4b30-a281-35fa2a47e717_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_0aa69867-5805-437b-831f-877b497945bd" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_380742db-dbf8-4b30-a281-35fa2a47e717" xlink:to="loc_srt_RangeMember_0aa69867-5805-437b-831f-877b497945bd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_4b1dffa1-d25f-4236-89e5-467922ac431c" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_0aa69867-5805-437b-831f-877b497945bd" xlink:to="loc_srt_MaximumMember_4b1dffa1-d25f-4236-89e5-467922ac431c" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/SegmentInformationSegmentFinancialDataDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#SegmentInformationSegmentFinancialDataDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/SegmentInformationSegmentFinancialDataDetails" xlink:type="extended" id="i6434d0b568c24450bdc05afebc0ebc64_SegmentInformationSegmentFinancialDataDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_ece8d328-d729-4880-bac1-7f3a0ea850e7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfOperatingSegments_b4faa8f6-be9a-46c6-8d46-8ffe246ee126" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NumberOfOperatingSegments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_ece8d328-d729-4880-bac1-7f3a0ea850e7" xlink:to="loc_us-gaap_NumberOfOperatingSegments_b4faa8f6-be9a-46c6-8d46-8ffe246ee126" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationRevenueAbstract_2cc7f075-6a95-4535-aa6f-c2a952a2a36a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentReportingInformationRevenueAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_ece8d328-d729-4880-bac1-7f3a0ea850e7" xlink:to="loc_us-gaap_SegmentReportingInformationRevenueAbstract_2cc7f075-6a95-4535-aa6f-c2a952a2a36a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_c2b1b1ee-5188-4aa8-8a80-74fd6c81a510" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationRevenueAbstract_2cc7f075-6a95-4535-aa6f-c2a952a2a36a" xlink:to="loc_us-gaap_Revenues_c2b1b1ee-5188-4aa8-8a80-74fd6c81a510" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingDisclosureOfOtherInformationAboutEntitysReportableSegmentsAbstract_bea2597c-4671-415e-8820-c730b14c1902" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentReportingDisclosureOfOtherInformationAboutEntitysReportableSegmentsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_ece8d328-d729-4880-bac1-7f3a0ea850e7" xlink:to="loc_us-gaap_SegmentReportingDisclosureOfOtherInformationAboutEntitysReportableSegmentsAbstract_bea2597c-4671-415e-8820-c730b14c1902" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromEquityMethodInvestments_626f1c0a-7d71-47ab-b612-eb5eb3025bc1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeLossFromEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingDisclosureOfOtherInformationAboutEntitysReportableSegmentsAbstract_bea2597c-4671-415e-8820-c730b14c1902" xlink:to="loc_us-gaap_IncomeLossFromEquityMethodInvestments_626f1c0a-7d71-47ab-b612-eb5eb3025bc1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SegmentAdjustedEBITDA_e14f1d2b-8c1b-438b-825d-313bc9a37895" xlink:href="paa-20211231.xsd#paa_SegmentAdjustedEBITDA"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingDisclosureOfOtherInformationAboutEntitysReportableSegmentsAbstract_bea2597c-4671-415e-8820-c730b14c1902" xlink:to="loc_paa_SegmentAdjustedEBITDA_e14f1d2b-8c1b-438b-825d-313bc9a37895" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_InvestmentAndAcquisitionCapitalExpenditures_ba63444c-5378-4939-b2cc-b8e691eaaa03" xlink:href="paa-20211231.xsd#paa_InvestmentAndAcquisitionCapitalExpenditures"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingDisclosureOfOtherInformationAboutEntitysReportableSegmentsAbstract_bea2597c-4671-415e-8820-c730b14c1902" xlink:to="loc_paa_InvestmentAndAcquisitionCapitalExpenditures_ba63444c-5378-4939-b2cc-b8e691eaaa03" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_MaintenanceCapitalExpenditures_65551ec2-05d8-48c0-9504-8cd697b2cde6" xlink:href="paa-20211231.xsd#paa_MaintenanceCapitalExpenditures"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingDisclosureOfOtherInformationAboutEntitysReportableSegmentsAbstract_bea2597c-4671-415e-8820-c730b14c1902" xlink:to="loc_paa_MaintenanceCapitalExpenditures_65551ec2-05d8-48c0-9504-8cd697b2cde6" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestments_3898a53a-14d2-4677-a7e2-da2593e3435b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingDisclosureOfOtherInformationAboutEntitysReportableSegmentsAbstract_bea2597c-4671-415e-8820-c730b14c1902" xlink:to="loc_us-gaap_EquityMethodInvestments_3898a53a-14d2-4677-a7e2-da2593e3435b" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_34bbd804-b4be-4489-a191-786d24a3b7d1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_ece8d328-d729-4880-bac1-7f3a0ea850e7" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_34bbd804-b4be-4489-a191-786d24a3b7d1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_a0e07ca1-fea5-48a9-8070-89e9b83a92f6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_34bbd804-b4be-4489-a191-786d24a3b7d1" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_a0e07ca1-fea5-48a9-8070-89e9b83a92f6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_a0e07ca1-fea5-48a9-8070-89e9b83a92f6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_a0e07ca1-fea5-48a9-8070-89e9b83a92f6" xlink:to="loc_us-gaap_SegmentDomain_a0e07ca1-fea5-48a9-8070-89e9b83a92f6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_58844986-ccd3-4b90-9000-8697d5eec0b7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_a0e07ca1-fea5-48a9-8070-89e9b83a92f6" xlink:to="loc_us-gaap_SegmentDomain_58844986-ccd3-4b90-9000-8697d5eec0b7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_CrudeOilSegmentMember_bb7b26ff-68b8-48b1-a1b2-aa0dbe3593f8" xlink:href="paa-20211231.xsd#paa_CrudeOilSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_58844986-ccd3-4b90-9000-8697d5eec0b7" xlink:to="loc_paa_CrudeOilSegmentMember_bb7b26ff-68b8-48b1-a1b2-aa0dbe3593f8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_NaturalGasLiquidsSegmentMember_14948a45-4add-4d66-9c25-c03679a73834" xlink:href="paa-20211231.xsd#paa_NaturalGasLiquidsSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_58844986-ccd3-4b90-9000-8697d5eec0b7" xlink:to="loc_paa_NaturalGasLiquidsSegmentMember_14948a45-4add-4d66-9c25-c03679a73834" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_9ada2aae-dc2f-445d-8408-4b65e651a591" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_34bbd804-b4be-4489-a191-786d24a3b7d1" xlink:to="loc_srt_ProductOrServiceAxis_9ada2aae-dc2f-445d-8408-4b65e651a591" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_9ada2aae-dc2f-445d-8408-4b65e651a591_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_9ada2aae-dc2f-445d-8408-4b65e651a591" xlink:to="loc_srt_ProductsAndServicesDomain_9ada2aae-dc2f-445d-8408-4b65e651a591_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_bc3fc5ff-b951-4348-9854-4739629ca732" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_9ada2aae-dc2f-445d-8408-4b65e651a591" xlink:to="loc_srt_ProductsAndServicesDomain_bc3fc5ff-b951-4348-9854-4739629ca732" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProductMember_bc082ff7-c370-4385-8c54-cbe682c1d505" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProductMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_bc3fc5ff-b951-4348-9854-4739629ca732" xlink:to="loc_us-gaap_ProductMember_bc082ff7-c370-4385-8c54-cbe682c1d505" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ServiceMember_9c060dcc-1c23-4f72-9cb9-4aa951b97026" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ServiceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_bc3fc5ff-b951-4348-9854-4739629ca732" xlink:to="loc_us-gaap_ServiceMember_9c060dcc-1c23-4f72-9cb9-4aa951b97026" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_1a394b39-3c7f-4056-a9ea-14afbdbec532" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_34bbd804-b4be-4489-a191-786d24a3b7d1" xlink:to="loc_srt_ConsolidationItemsAxis_1a394b39-3c7f-4056-a9ea-14afbdbec532" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_1a394b39-3c7f-4056-a9ea-14afbdbec532_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_1a394b39-3c7f-4056-a9ea-14afbdbec532" xlink:to="loc_srt_ConsolidationItemsDomain_1a394b39-3c7f-4056-a9ea-14afbdbec532_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_fced82c0-c4ad-4c3d-846a-3beb94ee46dc" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_1a394b39-3c7f-4056-a9ea-14afbdbec532" xlink:to="loc_srt_ConsolidationItemsDomain_fced82c0-c4ad-4c3d-846a-3beb94ee46dc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingSegmentsMember_9a572a81-7a73-4359-9e6a-e5d346a8e83c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_fced82c0-c4ad-4c3d-846a-3beb94ee46dc" xlink:to="loc_us-gaap_OperatingSegmentsMember_9a572a81-7a73-4359-9e6a-e5d346a8e83c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntersegmentEliminationMember_75879352-962d-4931-926e-a7cb20d8384f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IntersegmentEliminationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_fced82c0-c4ad-4c3d-846a-3beb94ee46dc" xlink:to="loc_us-gaap_IntersegmentEliminationMember_75879352-962d-4931-926e-a7cb20d8384f" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/SegmentInformationReconciliationofSegmentAdjustedEBITDADetails" xlink:type="simple" xlink:href="paa-20211231.xsd#SegmentInformationReconciliationofSegmentAdjustedEBITDADetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/SegmentInformationReconciliationofSegmentAdjustedEBITDADetails" xlink:type="extended" id="i59d97f3becc94c73910b445179786c6a_SegmentInformationReconciliationofSegmentAdjustedEBITDADetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingReconcilingItemForOperatingProfitLossFromSegmentToConsolidatedLineItems_9350fcc6-2c95-4fe7-ab02-b19c95d5c304" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentReportingReconcilingItemForOperatingProfitLossFromSegmentToConsolidatedLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SegmentAdjustedEBITDA_cb3c1dd2-e8e2-42f6-ac7e-01737ecc62e7" xlink:href="paa-20211231.xsd#paa_SegmentAdjustedEBITDA"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingReconcilingItemForOperatingProfitLossFromSegmentToConsolidatedLineItems_9350fcc6-2c95-4fe7-ab02-b19c95d5c304" xlink:to="loc_paa_SegmentAdjustedEBITDA_cb3c1dd2-e8e2-42f6-ac7e-01737ecc62e7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedAbstract_6b14600a-959a-4efa-be73-82fdc9c9778e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingReconcilingItemForOperatingProfitLossFromSegmentToConsolidatedLineItems_9350fcc6-2c95-4fe7-ab02-b19c95d5c304" xlink:to="loc_us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedAbstract_6b14600a-959a-4efa-be73-82fdc9c9778e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_DepreciationAndAmortizationOfUnconsolidatedEntities_58861371-b417-4ff6-9d4c-ee0012b62159" xlink:href="paa-20211231.xsd#paa_DepreciationAndAmortizationOfUnconsolidatedEntities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedAbstract_6b14600a-959a-4efa-be73-82fdc9c9778e" xlink:to="loc_paa_DepreciationAndAmortizationOfUnconsolidatedEntities_58861371-b417-4ff6-9d4c-ee0012b62159" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_GainsLossesFromDerivativeActivitiesAndInventoryValuationAdjustments_7355805d-551a-4ad6-8b93-27b99e38f3af" xlink:href="paa-20211231.xsd#paa_GainsLossesFromDerivativeActivitiesAndInventoryValuationAdjustments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedAbstract_6b14600a-959a-4efa-be73-82fdc9c9778e" xlink:to="loc_paa_GainsLossesFromDerivativeActivitiesAndInventoryValuationAdjustments_7355805d-551a-4ad6-8b93-27b99e38f3af" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_LongTermInventoryCostingAdjustments_02a5ec22-7a59-4d89-9d8f-7d0183b9e6aa" xlink:href="paa-20211231.xsd#paa_LongTermInventoryCostingAdjustments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedAbstract_6b14600a-959a-4efa-be73-82fdc9c9778e" xlink:to="loc_paa_LongTermInventoryCostingAdjustments_02a5ec22-7a59-4d89-9d8f-7d0183b9e6aa" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_DeficienciesUnderMinimumVolumeCommitmentsNet_ed37d092-c95a-4a79-8e10-f7c87e26f62c" xlink:href="paa-20211231.xsd#paa_DeficienciesUnderMinimumVolumeCommitmentsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedAbstract_6b14600a-959a-4efa-be73-82fdc9c9778e" xlink:to="loc_paa_DeficienciesUnderMinimumVolumeCommitmentsNet_ed37d092-c95a-4a79-8e10-f7c87e26f62c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_EquityIndexedCompensationExpenseAwardsThatWillOrMayBeSettledInUnits_4cdbf2c6-27d0-40c3-be81-6df7dc384d04" xlink:href="paa-20211231.xsd#paa_EquityIndexedCompensationExpenseAwardsThatWillOrMayBeSettledInUnits"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedAbstract_6b14600a-959a-4efa-be73-82fdc9c9778e" xlink:to="loc_paa_EquityIndexedCompensationExpenseAwardsThatWillOrMayBeSettledInUnits_4cdbf2c6-27d0-40c3-be81-6df7dc384d04" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_NetGainLossOnForeignCurrencyRevaluation_b18816c9-3b71-4623-a99a-387e0c33e430" xlink:href="paa-20211231.xsd#paa_NetGainLossOnForeignCurrencyRevaluation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedAbstract_6b14600a-959a-4efa-be73-82fdc9c9778e" xlink:to="loc_paa_NetGainLossOnForeignCurrencyRevaluation_b18816c9-3b71-4623-a99a-387e0c33e430" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SignificantCostsRelatedToLegalAndEnvironmentalRemediationMatters_7421d9d9-5ad1-447b-b07c-399b6ebfefa0" xlink:href="paa-20211231.xsd#paa_SignificantCostsRelatedToLegalAndEnvironmentalRemediationMatters"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedAbstract_6b14600a-959a-4efa-be73-82fdc9c9778e" xlink:to="loc_paa_SignificantCostsRelatedToLegalAndEnvironmentalRemediationMatters_7421d9d9-5ad1-447b-b07c-399b6ebfefa0" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_SignificantTransactionRelatedExpenses_a769c2a3-b871-4bdc-ab2b-3aa431cf9f40" xlink:href="paa-20211231.xsd#paa_SignificantTransactionRelatedExpenses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedAbstract_6b14600a-959a-4efa-be73-82fdc9c9778e" xlink:to="loc_paa_SignificantTransactionRelatedExpenses_a769c2a3-b871-4bdc-ab2b-3aa431cf9f40" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_AdjustedEBITDAAttributableToNoncontrollingInterests_769311cd-1e4c-4ea1-b48d-b49a60626e66" xlink:href="paa-20211231.xsd#paa_AdjustedEBITDAAttributableToNoncontrollingInterests"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedAbstract_6b14600a-959a-4efa-be73-82fdc9c9778e" xlink:to="loc_paa_AdjustedEBITDAAttributableToNoncontrollingInterests_769311cd-1e4c-4ea1-b48d-b49a60626e66" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationDepletionAndAmortization_5b528a0f-88b4-4ab4-a5c6-64f19dcf38af" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DepreciationDepletionAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedAbstract_6b14600a-959a-4efa-be73-82fdc9c9778e" xlink:to="loc_us-gaap_DepreciationDepletionAndAmortization_5b528a0f-88b4-4ab4-a5c6-64f19dcf38af" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnSalesOfAssetsAndAssetImpairmentCharges_be132f72-cfb1-4907-a924-2afc59c5ccea" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GainLossOnSalesOfAssetsAndAssetImpairmentCharges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedAbstract_6b14600a-959a-4efa-be73-82fdc9c9778e" xlink:to="loc_us-gaap_GainLossOnSalesOfAssetsAndAssetImpairmentCharges_be132f72-cfb1-4907-a924-2afc59c5ccea" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillImpairmentLoss_6a9623b3-8066-4963-9657-846d1bbfa02c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GoodwillImpairmentLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedAbstract_6b14600a-959a-4efa-be73-82fdc9c9778e" xlink:to="loc_us-gaap_GoodwillImpairmentLoss_6a9623b3-8066-4963-9657-846d1bbfa02c" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_GainOnImpairmentOfInvestmentsInUnconsolidatedEntitiesNet_2125cffc-9115-4960-8783-d499f7abc366" xlink:href="paa-20211231.xsd#paa_GainOnImpairmentOfInvestmentsInUnconsolidatedEntitiesNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedAbstract_6b14600a-959a-4efa-be73-82fdc9c9778e" xlink:to="loc_paa_GainOnImpairmentOfInvestmentsInUnconsolidatedEntitiesNet_2125cffc-9115-4960-8783-d499f7abc366" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpense_eeac5dd2-c7b1-41d7-a267-4a3bb7a034c0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedAbstract_6b14600a-959a-4efa-be73-82fdc9c9778e" xlink:to="loc_us-gaap_InterestExpense_eeac5dd2-c7b1-41d7-a267-4a3bb7a034c0" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_94741623-a0a3-4a5c-9fd1-9662fa9a04de" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherNonoperatingIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedAbstract_6b14600a-959a-4efa-be73-82fdc9c9778e" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_94741623-a0a3-4a5c-9fd1-9662fa9a04de" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_da096ebc-8536-428e-a29a-aebc3c68a93f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedAbstract_6b14600a-959a-4efa-be73-82fdc9c9778e" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_da096ebc-8536-428e-a29a-aebc3c68a93f" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_90f8ebc3-f2d4-4a46-b537-45c845431190" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedAbstract_6b14600a-959a-4efa-be73-82fdc9c9778e" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_90f8ebc3-f2d4-4a46-b537-45c845431190" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_4838a3a9-823b-404e-b8dd-6926bb3859f2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedAbstract_6b14600a-959a-4efa-be73-82fdc9c9778e" xlink:to="loc_us-gaap_ProfitLoss_4838a3a9-823b-404e-b8dd-6926bb3859f2" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_cf0c25fc-2ce0-4672-aabf-01c8508727da" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLossAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedAbstract_6b14600a-959a-4efa-be73-82fdc9c9778e" xlink:to="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_cf0c25fc-2ce0-4672-aabf-01c8508727da" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_524767dc-bda9-4020-a116-4d07c9f92910" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedAbstract_6b14600a-959a-4efa-be73-82fdc9c9778e" xlink:to="loc_us-gaap_NetIncomeLoss_524767dc-bda9-4020-a116-4d07c9f92910" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedTable_fdc6075a-6ea1-4531-89a5-d882238c3b77" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingReconcilingItemForOperatingProfitLossFromSegmentToConsolidatedLineItems_9350fcc6-2c95-4fe7-ab02-b19c95d5c304" xlink:to="loc_us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedTable_fdc6075a-6ea1-4531-89a5-d882238c3b77" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_800c3b54-c788-45dd-a7cd-0cc7885243ce" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LossContingenciesByNatureOfContingencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedTable_fdc6075a-6ea1-4531-89a5-d882238c3b77" xlink:to="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_800c3b54-c788-45dd-a7cd-0cc7885243ce" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyNatureDomain_800c3b54-c788-45dd-a7cd-0cc7885243ce_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LossContingencyNatureDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_800c3b54-c788-45dd-a7cd-0cc7885243ce" xlink:to="loc_us-gaap_LossContingencyNatureDomain_800c3b54-c788-45dd-a7cd-0cc7885243ce_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyNatureDomain_703a6e6d-03b5-4064-9a3b-4d9c65258e5c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LossContingencyNatureDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_800c3b54-c788-45dd-a7cd-0cc7885243ce" xlink:to="loc_us-gaap_LossContingencyNatureDomain_703a6e6d-03b5-4064-9a3b-4d9c65258e5c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_paa_Line901IncidentMember_e645c0cd-5115-458c-9729-460768fb3f52" xlink:href="paa-20211231.xsd#paa_Line901IncidentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingencyNatureDomain_703a6e6d-03b5-4064-9a3b-4d9c65258e5c" xlink:to="loc_paa_Line901IncidentMember_e645c0cd-5115-458c-9729-460768fb3f52" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.paalp.com/role/SegmentInformationGeographicDataDetails" xlink:type="simple" xlink:href="paa-20211231.xsd#SegmentInformationGeographicDataDetails"/>
  <link:definitionLink xlink:role="http://www.paalp.com/role/SegmentInformationGeographicDataDetails" xlink:type="extended" id="idb049e26de4140d6870f8be06f11f502_SegmentInformationGeographicDataDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems_71bfbdb7-60b9-4bf9-ac9d-b2930739a8c3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_307a46dc-7f54-4f06-b7f1-a78c827eb403" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems_71bfbdb7-60b9-4bf9-ac9d-b2930739a8c3" xlink:to="loc_us-gaap_Revenues_307a46dc-7f54-4f06-b7f1-a78c827eb403" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncurrentAssets_0900a740-fcce-457a-af8a-98645281d3d3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NoncurrentAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems_71bfbdb7-60b9-4bf9-ac9d-b2930739a8c3" xlink:to="loc_us-gaap_NoncurrentAssets_0900a740-fcce-457a-af8a-98645281d3d3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable_be4dbe04-a2d1-44bf-8763-356b257ecd78" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems_71bfbdb7-60b9-4bf9-ac9d-b2930739a8c3" xlink:to="loc_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable_be4dbe04-a2d1-44bf-8763-356b257ecd78" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_5f5e34e7-f44a-4538-8e46-fbd36570ce19" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable_be4dbe04-a2d1-44bf-8763-356b257ecd78" xlink:to="loc_srt_StatementGeographicalAxis_5f5e34e7-f44a-4538-8e46-fbd36570ce19" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_5f5e34e7-f44a-4538-8e46-fbd36570ce19_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_5f5e34e7-f44a-4538-8e46-fbd36570ce19" xlink:to="loc_srt_SegmentGeographicalDomain_5f5e34e7-f44a-4538-8e46-fbd36570ce19_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_b30d32b6-6113-4379-924d-d980b9352f76" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_5f5e34e7-f44a-4538-8e46-fbd36570ce19" xlink:to="loc_srt_SegmentGeographicalDomain_b30d32b6-6113-4379-924d-d980b9352f76" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_US_d6848a59-aac6-4b54-a3dd-0538095c7ddc" xlink:href="https://xbrl.sec.gov/country/2021/country-2021.xsd#country_US"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_b30d32b6-6113-4379-924d-d980b9352f76" xlink:to="loc_country_US_d6848a59-aac6-4b54-a3dd-0538095c7ddc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_CA_797ed84c-9bb4-4596-82ce-ff8746c645cc" xlink:href="https://xbrl.sec.gov/country/2021/country-2021.xsd#country_CA"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_b30d32b6-6113-4379-924d-d980b9352f76" xlink:to="loc_country_CA_797ed84c-9bb4-4596-82ce-ff8746c645cc" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists" xlink:type="simple" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-roles-2021-01-31.xsd#eedm"/>
  <link:definitionLink xlink:role="http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization" xlink:type="arc" order="0"/>
  </link:definitionLink>
</link:linkbase>
