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

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019ffbcd-18e9-7a82-bdca-b00c71a9f277,g:23dce543-6499-44b6-bbb9-5eebdc60ea56-->
<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.kniferiver.com/role/ConsolidatedStatementsofOperations" xlink:type="simple" xlink:href="knf-20260930.xsd#ConsolidatedStatementsofOperations"/>
  <link:definitionLink xlink:role="http://www.kniferiver.com/role/ConsolidatedStatementsofOperations" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_019ffbcd-1aed-726d-8710-3e9a1ab27f6c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_019ffbcd-1aed-75f5-9795-90babe81a025" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_019ffbcd-1aed-726d-8710-3e9a1ab27f6c" xlink:to="loc_us-gaap_StatementTable_019ffbcd-1aed-75f5-9795-90babe81a025" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_019ffbcd-1aed-78b5-96b6-5c80c39d18ae" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019ffbcd-1aed-75f5-9795-90babe81a025" xlink:to="loc_srt_ProductOrServiceAxis_019ffbcd-1aed-78b5-96b6-5c80c39d18ae" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019ffbcd-1aed-78b5-96b6-5c80c39d18ae_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_019ffbcd-1aed-78b5-96b6-5c80c39d18ae" xlink:to="loc_srt_ProductsAndServicesDomain_019ffbcd-1aed-78b5-96b6-5c80c39d18ae_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019ffbcd-1aed-728a-b2ca-39bb73efcb67" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_019ffbcd-1aed-78b5-96b6-5c80c39d18ae" xlink:to="loc_srt_ProductsAndServicesDomain_019ffbcd-1aed-728a-b2ca-39bb73efcb67" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProductMember_019ffbcd-1aed-77e2-8d88-432c423854af" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProductMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019ffbcd-1aed-728a-b2ca-39bb73efcb67" xlink:to="loc_us-gaap_ProductMember_019ffbcd-1aed-77e2-8d88-432c423854af" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ServiceMember_019ffbcd-1aed-7fdd-9fed-975fd892f4ac" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ServiceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019ffbcd-1aed-728a-b2ca-39bb73efcb67" xlink:to="loc_us-gaap_ServiceMember_019ffbcd-1aed-7fdd-9fed-975fd892f4ac" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenuesAbstract_019ffbcd-1aed-79bb-88c4-f67cba7973c6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenuesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019ffbcd-1aed-726d-8710-3e9a1ab27f6c" xlink:to="loc_us-gaap_RevenuesAbstract_019ffbcd-1aed-79bb-88c4-f67cba7973c6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_019ffbcd-1aed-750e-816a-48493a20625e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_019ffbcd-1aed-79bb-88c4-f67cba7973c6" xlink:to="loc_us-gaap_Revenues_019ffbcd-1aed-750e-816a-48493a20625e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingExpensesAbstract_019ffbcd-1aed-7fc1-9bdd-444659f194eb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingExpensesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019ffbcd-1aed-726d-8710-3e9a1ab27f6c" xlink:to="loc_us-gaap_OperatingExpensesAbstract_019ffbcd-1aed-7fc1-9bdd-444659f194eb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfRevenue_019ffbcd-1aed-7b6f-ad37-2eab54ead819" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CostOfRevenue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_019ffbcd-1aed-7fc1-9bdd-444659f194eb" xlink:to="loc_us-gaap_CostOfRevenue_019ffbcd-1aed-7b6f-ad37-2eab54ead819" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GrossProfit_019ffbcd-1aed-7ae1-a648-17138cedba34" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GrossProfit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019ffbcd-1aed-726d-8710-3e9a1ab27f6c" xlink:to="loc_us-gaap_GrossProfit_019ffbcd-1aed-7ae1-a648-17138cedba34" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpense_019ffbcd-1aed-7787-8a43-c4f5d77fa634" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SellingGeneralAndAdministrativeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019ffbcd-1aed-726d-8710-3e9a1ab27f6c" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpense_019ffbcd-1aed-7787-8a43-c4f5d77fa634" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_019ffbcd-1aed-74c9-8547-d34d02f60680" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019ffbcd-1aed-726d-8710-3e9a1ab27f6c" xlink:to="loc_us-gaap_OperatingIncomeLoss_019ffbcd-1aed-74c9-8547-d34d02f60680" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseNonoperating_019ffbcd-1aed-7518-9fb7-c3df561e5bf7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestExpenseNonoperating"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019ffbcd-1aed-726d-8710-3e9a1ab27f6c" xlink:to="loc_us-gaap_InterestExpenseNonoperating_019ffbcd-1aed-7518-9fb7-c3df561e5bf7" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_019ffbcd-1aed-7b2b-88f3-7ad32490fda1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherNonoperatingIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019ffbcd-1aed-726d-8710-3e9a1ab27f6c" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_019ffbcd-1aed-7b2b-88f3-7ad32490fda1" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019ffbcd-1aed-7a2b-ab37-648c30bf5a36" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019ffbcd-1aed-726d-8710-3e9a1ab27f6c" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019ffbcd-1aed-7a2b-ab37-648c30bf5a36" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_019ffbcd-1aed-7a13-ac1d-94ce39551d79" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019ffbcd-1aed-726d-8710-3e9a1ab27f6c" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_019ffbcd-1aed-7a13-ac1d-94ce39551d79" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_019ffbcd-1aed-7bd8-9ed9-727704d9871f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019ffbcd-1aed-726d-8710-3e9a1ab27f6c" xlink:to="loc_us-gaap_NetIncomeLoss_019ffbcd-1aed-7bd8-9ed9-727704d9871f" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareAbstract_019ffbcd-1aed-7557-922a-6430c24a7c3d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EarningsPerShareAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019ffbcd-1aed-726d-8710-3e9a1ab27f6c" xlink:to="loc_us-gaap_EarningsPerShareAbstract_019ffbcd-1aed-7557-922a-6430c24a7c3d" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasic_019ffbcd-1aed-7b81-9973-df7508e2586d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EarningsPerShareBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareAbstract_019ffbcd-1aed-7557-922a-6430c24a7c3d" xlink:to="loc_us-gaap_EarningsPerShareBasic_019ffbcd-1aed-7b81-9973-df7508e2586d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareDiluted_019ffbcd-1aed-76b4-8b88-58fabeb9229d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EarningsPerShareDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareAbstract_019ffbcd-1aed-7557-922a-6430c24a7c3d" xlink:to="loc_us-gaap_EarningsPerShareDiluted_019ffbcd-1aed-76b4-8b88-58fabeb9229d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingDilutedDisclosureItemsAbstract_019ffbcd-1aed-765e-b38d-676a0d3f3815" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingDilutedDisclosureItemsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019ffbcd-1aed-726d-8710-3e9a1ab27f6c" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingDilutedDisclosureItemsAbstract_019ffbcd-1aed-765e-b38d-676a0d3f3815" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_019ffbcd-1aed-74f0-b8fb-0e115ede1787" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingDilutedDisclosureItemsAbstract_019ffbcd-1aed-765e-b38d-676a0d3f3815" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_019ffbcd-1aed-74f0-b8fb-0e115ede1787" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019ffbcd-1aed-7a23-a986-b135760edfbf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingDilutedDisclosureItemsAbstract_019ffbcd-1aed-765e-b38d-676a0d3f3815" xlink:to="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019ffbcd-1aed-7a23-a986-b135760edfbf" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.kniferiver.com/role/ConsolidatedStatementsofEquity" xlink:type="simple" xlink:href="knf-20260930.xsd#ConsolidatedStatementsofEquity"/>
  <link:definitionLink xlink:role="http://www.kniferiver.com/role/ConsolidatedStatementsofEquity" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_019ffbcd-1aed-797c-a239-3af3eaa8f199" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_019ffbcd-1aed-7208-a96f-b1b827cabb27" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_019ffbcd-1aed-797c-a239-3af3eaa8f199" xlink:to="loc_us-gaap_StatementTable_019ffbcd-1aed-7208-a96f-b1b827cabb27" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_019ffbcd-1aed-7e34-be4e-bab0508fde15" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019ffbcd-1aed-7208-a96f-b1b827cabb27" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_019ffbcd-1aed-7e34-be4e-bab0508fde15" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019ffbcd-1aed-7e34-be4e-bab0508fde15_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019ffbcd-1aed-7e34-be4e-bab0508fde15" xlink:to="loc_us-gaap_EquityComponentDomain_019ffbcd-1aed-7e34-be4e-bab0508fde15_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019ffbcd-1aed-73e1-b0d5-bbcecc21ab46" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019ffbcd-1aed-7e34-be4e-bab0508fde15" xlink:to="loc_us-gaap_EquityComponentDomain_019ffbcd-1aed-73e1-b0d5-bbcecc21ab46" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_019ffbcd-1aed-7b99-b424-5c82041798de" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019ffbcd-1aed-73e1-b0d5-bbcecc21ab46" xlink:to="loc_us-gaap_CommonStockMember_019ffbcd-1aed-7b99-b424-5c82041798de" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_019ffbcd-1aed-78d7-bad6-840f8e5995ef" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019ffbcd-1aed-73e1-b0d5-bbcecc21ab46" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_019ffbcd-1aed-78d7-bad6-840f8e5995ef" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_019ffbcd-1aed-784c-86d6-f6ad6db1d066" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019ffbcd-1aed-73e1-b0d5-bbcecc21ab46" xlink:to="loc_us-gaap_RetainedEarningsMember_019ffbcd-1aed-784c-86d6-f6ad6db1d066" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonMember_019ffbcd-1aed-73b1-a6e4-cc7f0b0f0562" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TreasuryStockCommonMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019ffbcd-1aed-73e1-b0d5-bbcecc21ab46" xlink:to="loc_us-gaap_TreasuryStockCommonMember_019ffbcd-1aed-73b1-a6e4-cc7f0b0f0562" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_019ffbcd-1aed-7886-b4e6-3b6a3eb897d1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019ffbcd-1aed-73e1-b0d5-bbcecc21ab46" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_019ffbcd-1aed-7886-b4e6-3b6a3eb897d1" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019ffbcd-1aed-742d-a7c2-36956315e2ff" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019ffbcd-1aed-797c-a239-3af3eaa8f199" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019ffbcd-1aed-742d-a7c2-36956315e2ff" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_019ffbcd-1aed-73d7-a663-1312436422a8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019ffbcd-1aed-742d-a7c2-36956315e2ff" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_019ffbcd-1aed-73d7-a663-1312436422a8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_019ffbcd-1aed-7439-be08-9dd93c86b9e8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019ffbcd-1aed-742d-a7c2-36956315e2ff" xlink:to="loc_us-gaap_StockholdersEquity_019ffbcd-1aed-7439-be08-9dd93c86b9e8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonShares_019ffbcd-1aed-7822-9714-42c5b567abf4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TreasuryStockCommonShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019ffbcd-1aed-742d-a7c2-36956315e2ff" xlink:to="loc_us-gaap_TreasuryStockCommonShares_019ffbcd-1aed-7822-9714-42c5b567abf4" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_019ffbcd-1aed-72b8-bf21-6498e442bc38" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019ffbcd-1aed-742d-a7c2-36956315e2ff" xlink:to="loc_us-gaap_NetIncomeLoss_019ffbcd-1aed-72b8-bf21-6498e442bc38" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_019ffbcd-1aed-76e4-ba07-f6ffb9abc19f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019ffbcd-1aed-742d-a7c2-36956315e2ff" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_019ffbcd-1aed-76e4-ba07-f6ffb9abc19f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationAndExerciseOfStockOptions_019ffbcd-1aed-7baf-b1d0-251a13146b64" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationAndExerciseOfStockOptions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019ffbcd-1aed-742d-a7c2-36956315e2ff" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationAndExerciseOfStockOptions_019ffbcd-1aed-7baf-b1d0-251a13146b64" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockSharesIssuedNetOfSharesForTaxWithholdings_019ffbcd-1aed-7f3b-a96e-9496d307dd44" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedStockSharesIssuedNetOfSharesForTaxWithholdings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019ffbcd-1aed-742d-a7c2-36956315e2ff" xlink:to="loc_us-gaap_RestrictedStockSharesIssuedNetOfSharesForTaxWithholdings_019ffbcd-1aed-7f3b-a96e-9496d307dd44" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockValueSharesIssuedNetOfTaxWithholdings_019ffbcd-1aed-7d57-8c84-d75284f6265f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedStockValueSharesIssuedNetOfTaxWithholdings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019ffbcd-1aed-742d-a7c2-36956315e2ff" xlink:to="loc_us-gaap_RestrictedStockValueSharesIssuedNetOfTaxWithholdings_019ffbcd-1aed-7d57-8c84-d75284f6265f" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesIssuedForServices_019ffbcd-1aed-7cd9-9b29-e53bddb3836c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodSharesIssuedForServices"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019ffbcd-1aed-742d-a7c2-36956315e2ff" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesIssuedForServices_019ffbcd-1aed-7cd9-9b29-e53bddb3836c" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_019ffbcd-1aed-7485-a5f8-b9796b96f8e6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonShares_019ffbcd-1aed-7990-a932-057f5d299376" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TreasuryStockCommonShares"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_019ffbcd-1aed-761b-95ea-0dc75cd1a760" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.kniferiver.com/role/BasisofPresentationNarrativeDetails" xlink:type="simple" xlink:href="knf-20260930.xsd#BasisofPresentationNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.kniferiver.com/role/BasisofPresentationNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_019ffbcd-1aed-78eb-92f8-d34119fc6678" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_019ffbcd-1aed-70a0-be7f-a0523dee2b72" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_019ffbcd-1aed-78eb-92f8-d34119fc6678" xlink:to="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_019ffbcd-1aed-70a0-be7f-a0523dee2b72" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_01a177f8-ff3a-71b4-93b2-8d9b81d0d15e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_019ffbcd-1aed-70a0-be7f-a0523dee2b72" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_01a177f8-ff3a-71b4-93b2-8d9b81d0d15e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_01a177f8-ff3a-71b4-93b2-8d9b81d0d15e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_01a177f8-ff3a-71b4-93b2-8d9b81d0d15e" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_01a177f8-ff3a-71b4-93b2-8d9b81d0d15e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_01a177f8-ff3a-7766-8bf2-8264ef0cda51" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_01a177f8-ff3a-71b4-93b2-8d9b81d0d15e" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_01a177f8-ff3a-7766-8bf2-8264ef0cda51" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_StrataCorporationMember_01a177f8-ff3a-7d8b-ab8a-67a6566ab1c3" xlink:href="knf-20260930.xsd#knf_StrataCorporationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_01a177f8-ff3a-7766-8bf2-8264ef0cda51" xlink:to="loc_knf_StrataCorporationMember_01a177f8-ff3a-7d8b-ab8a-67a6566ab1c3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_019ffbcd-1aed-79cb-bcee-50f89d536a9a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_019ffbcd-1aed-70a0-be7f-a0523dee2b72" xlink:to="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_019ffbcd-1aed-79cb-bcee-50f89d536a9a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivableTypeDomain_019ffbcd-1aed-79cb-bcee-50f89d536a9a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReceivableTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_019ffbcd-1aed-79cb-bcee-50f89d536a9a" xlink:to="loc_us-gaap_ReceivableTypeDomain_019ffbcd-1aed-79cb-bcee-50f89d536a9a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivableTypeDomain_019ffbcd-1aed-7969-84e3-3edd40d5dea4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReceivableTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_019ffbcd-1aed-79cb-bcee-50f89d536a9a" xlink:to="loc_us-gaap_ReceivableTypeDomain_019ffbcd-1aed-7969-84e3-3edd40d5dea4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TradeAccountsReceivableMember_019ffbcd-1aed-753f-9bcb-d87988ee57c3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TradeAccountsReceivableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReceivableTypeDomain_019ffbcd-1aed-7969-84e3-3edd40d5dea4" xlink:to="loc_us-gaap_TradeAccountsReceivableMember_019ffbcd-1aed-753f-9bcb-d87988ee57c3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationTypeAxis_019ffbcd-1aed-7154-b32c-37f38710d326" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReclassificationTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_019ffbcd-1aed-70a0-be7f-a0523dee2b72" xlink:to="loc_us-gaap_ReclassificationTypeAxis_019ffbcd-1aed-7154-b32c-37f38710d326" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationTypeDomain_019ffbcd-1aed-7154-b32c-37f38710d326_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReclassificationTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ReclassificationTypeAxis_019ffbcd-1aed-7154-b32c-37f38710d326" xlink:to="loc_us-gaap_ReclassificationTypeDomain_019ffbcd-1aed-7154-b32c-37f38710d326_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationTypeDomain_019ffbcd-1aed-7a6d-b25a-93e6ba9373dc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReclassificationTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ReclassificationTypeAxis_019ffbcd-1aed-7154-b32c-37f38710d326" xlink:to="loc_us-gaap_ReclassificationTypeDomain_019ffbcd-1aed-7a6d-b25a-93e6ba9373dc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOtherMember_019ffbcd-1aed-776f-a23e-f79a8fc43f7c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReclassificationOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationTypeDomain_019ffbcd-1aed-7a6d-b25a-93e6ba9373dc" xlink:to="loc_us-gaap_ReclassificationOtherMember_019ffbcd-1aed-776f-a23e-f79a8fc43f7c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferred1_01a177f8-ff3a-7897-a887-6bf06937532b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationConsiderationTransferred1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_019ffbcd-1aed-78eb-92f8-d34119fc6678" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferred1_01a177f8-ff3a-7897-a887-6bf06937532b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionContractorReceivableRetainage_019ffbcd-1aed-747b-934c-91f423c06d53" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConstructionContractorReceivableRetainage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_019ffbcd-1aed-78eb-92f8-d34119fc6678" xlink:to="loc_us-gaap_ConstructionContractorReceivableRetainage_019ffbcd-1aed-747b-934c-91f423c06d53" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerAssetNet_019ffbcd-1aed-7303-a288-e43ad10509ff" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ContractWithCustomerAssetNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_019ffbcd-1aed-78eb-92f8-d34119fc6678" xlink:to="loc_us-gaap_ContractWithCustomerAssetNet_019ffbcd-1aed-7303-a288-e43ad10509ff" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiability_019ffbcd-1aed-7e40-a16c-7b418d8cd3b9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ContractWithCustomerLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_019ffbcd-1aed-78eb-92f8-d34119fc6678" xlink:to="loc_us-gaap_ContractWithCustomerLiability_019ffbcd-1aed-7e40-a16c-7b418d8cd3b9" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.kniferiver.com/role/ReceivablesandAllowanceforExpectedCreditLossesScheduleofReceivablesDetails" xlink:type="simple" xlink:href="knf-20260930.xsd#ReceivablesandAllowanceforExpectedCreditLossesScheduleofReceivablesDetails"/>
  <link:definitionLink xlink:role="http://www.kniferiver.com/role/ReceivablesandAllowanceforExpectedCreditLossesScheduleofReceivablesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019ffbcd-1aed-7758-8b65-8c6c2e211a93" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsNotesAndLoansReceivableLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019ffbcd-1aed-749a-b4b6-5b3fda52e7e6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019ffbcd-1aed-7758-8b65-8c6c2e211a93" xlink:to="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019ffbcd-1aed-749a-b4b6-5b3fda52e7e6" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_019ffbcd-1aed-738d-854a-62c805a9141c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019ffbcd-1aed-749a-b4b6-5b3fda52e7e6" xlink:to="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_019ffbcd-1aed-738d-854a-62c805a9141c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivableTypeDomain_019ffbcd-1aed-738d-854a-62c805a9141c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReceivableTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_019ffbcd-1aed-738d-854a-62c805a9141c" xlink:to="loc_us-gaap_ReceivableTypeDomain_019ffbcd-1aed-738d-854a-62c805a9141c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivableTypeDomain_019ffbcd-1aed-7551-a8ed-f91ecb6619a8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReceivableTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_019ffbcd-1aed-738d-854a-62c805a9141c" xlink:to="loc_us-gaap_ReceivableTypeDomain_019ffbcd-1aed-7551-a8ed-f91ecb6619a8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TradeAccountsReceivableMember_019ffbcd-1aed-793f-ad32-2a4a890eb540" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TradeAccountsReceivableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReceivableTypeDomain_019ffbcd-1aed-7551-a8ed-f91ecb6619a8" xlink:to="loc_us-gaap_TradeAccountsReceivableMember_019ffbcd-1aed-793f-ad32-2a4a890eb540" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsAndOtherReceivablesNetCurrent_019ffbcd-1aed-73ba-a8b2-fa97c8b70d8f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsAndOtherReceivablesNetCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019ffbcd-1aed-7758-8b65-8c6c2e211a93" xlink:to="loc_us-gaap_AccountsAndOtherReceivablesNetCurrent_019ffbcd-1aed-73ba-a8b2-fa97c8b70d8f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BilledContractReceivables_019ffbcd-1aed-7fa9-99f3-9617965bed43" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BilledContractReceivables"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019ffbcd-1aed-7758-8b65-8c6c2e211a93" xlink:to="loc_us-gaap_BilledContractReceivables_019ffbcd-1aed-7fa9-99f3-9617965bed43" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableGross_019ffbcd-1aed-7e3b-8ddc-99f2b5339599" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsReceivableGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019ffbcd-1aed-7758-8b65-8c6c2e211a93" xlink:to="loc_us-gaap_AccountsReceivableGross_019ffbcd-1aed-7e3b-8ddc-99f2b5339599" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsReceivable_019ffbcd-1aed-7af1-a59a-d692b07be156" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019ffbcd-1aed-7758-8b65-8c6c2e211a93" xlink:to="loc_us-gaap_AllowanceForDoubtfulAccountsReceivable_019ffbcd-1aed-7af1-a59a-d692b07be156" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableNet_019ffbcd-1aed-75d9-9f15-dfd0633fd1cf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsReceivableNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019ffbcd-1aed-7758-8b65-8c6c2e211a93" xlink:to="loc_us-gaap_AccountsReceivableNet_019ffbcd-1aed-75d9-9f15-dfd0633fd1cf" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.kniferiver.com/role/ReceivablesandAllowanceforExpectedCreditLossesScheduleofDetailsofExpectedCreditLossesDetails" xlink:type="simple" xlink:href="knf-20260930.xsd#ReceivablesandAllowanceforExpectedCreditLossesScheduleofDetailsofExpectedCreditLossesDetails"/>
  <link:definitionLink xlink:role="http://www.kniferiver.com/role/ReceivablesandAllowanceforExpectedCreditLossesScheduleofDetailsofExpectedCreditLossesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_019ffbcd-1aee-7316-90a9-ca511c6088a0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_019ffbcd-1aee-71e5-9808-452c3b493f95" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisaggregationOfRevenueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019ffbcd-1aee-7316-90a9-ca511c6088a0" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_019ffbcd-1aee-71e5-9808-452c3b493f95" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_019ffbcd-1aee-7e5c-86ba-0ad8d03b2949" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_019ffbcd-1aee-71e5-9808-452c3b493f95" xlink:to="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_019ffbcd-1aee-7e5c-86ba-0ad8d03b2949" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivableTypeDomain_019ffbcd-1aee-7e5c-86ba-0ad8d03b2949_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReceivableTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_019ffbcd-1aee-7e5c-86ba-0ad8d03b2949" xlink:to="loc_us-gaap_ReceivableTypeDomain_019ffbcd-1aee-7e5c-86ba-0ad8d03b2949_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivableTypeDomain_019ffbcd-1aee-7232-aed8-a40b6f4377bc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReceivableTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_019ffbcd-1aee-7e5c-86ba-0ad8d03b2949" xlink:to="loc_us-gaap_ReceivableTypeDomain_019ffbcd-1aee-7232-aed8-a40b6f4377bc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TradeAccountsReceivableMember_019ffbcd-1aee-7f24-a49a-069d62d8f00d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TradeAccountsReceivableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReceivableTypeDomain_019ffbcd-1aee-7232-aed8-a40b6f4377bc" xlink:to="loc_us-gaap_TradeAccountsReceivableMember_019ffbcd-1aee-7f24-a49a-069d62d8f00d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_019ffbcd-1aee-76e4-af5e-eba5fe1817cd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_019ffbcd-1aee-71e5-9808-452c3b493f95" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_019ffbcd-1aee-76e4-af5e-eba5fe1817cd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019ffbcd-1aee-76e4-af5e-eba5fe1817cd_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019ffbcd-1aee-76e4-af5e-eba5fe1817cd" xlink:to="loc_us-gaap_SegmentDomain_019ffbcd-1aee-76e4-af5e-eba5fe1817cd_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019ffbcd-1aee-7330-87ea-bae282ac9799" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019ffbcd-1aee-76e4-af5e-eba5fe1817cd" xlink:to="loc_us-gaap_SegmentDomain_019ffbcd-1aee-7330-87ea-bae282ac9799" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_WestSegmentMember_019ffbcd-1aee-75f3-b1f1-fbc75e2e8627" xlink:href="knf-20260930.xsd#knf_WestSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019ffbcd-1aee-7330-87ea-bae282ac9799" xlink:to="loc_knf_WestSegmentMember_019ffbcd-1aee-75f3-b1f1-fbc75e2e8627" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_MountainSegmentMember_019ffbcd-1aee-76f6-bcf0-f08693952f09" xlink:href="knf-20260930.xsd#knf_MountainSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019ffbcd-1aee-7330-87ea-bae282ac9799" xlink:to="loc_knf_MountainSegmentMember_019ffbcd-1aee-76f6-bcf0-f08693952f09" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_CentralSegmentMember_019ffbcd-1aee-791a-a5f2-63c6b03101f8" xlink:href="knf-20260930.xsd#knf_CentralSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019ffbcd-1aee-7330-87ea-bae282ac9799" xlink:to="loc_knf_CentralSegmentMember_019ffbcd-1aee-791a-a5f2-63c6b03101f8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_EnergyServicesSegmentMember_019ffbcd-1aee-7e37-a796-4835bf381841" xlink:href="knf-20260930.xsd#knf_EnergyServicesSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019ffbcd-1aee-7330-87ea-bae282ac9799" xlink:to="loc_knf_EnergyServicesSegmentMember_019ffbcd-1aee-7e37-a796-4835bf381841" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward_019ffbcd-1aee-78bf-8f4f-78243e487736" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019ffbcd-1aee-7316-90a9-ca511c6088a0" xlink:to="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward_019ffbcd-1aee-78bf-8f4f-78243e487736" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsReceivable_019ffbcd-1aee-7d64-8c3d-30209648e2be" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward_019ffbcd-1aee-78bf-8f4f-78243e487736" xlink:to="loc_us-gaap_AllowanceForDoubtfulAccountsReceivable_019ffbcd-1aee-7d64-8c3d-30209648e2be" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProvisionForDoubtfulAccounts_019ffbcd-1aee-70f8-9dde-3655a24d806b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProvisionForDoubtfulAccounts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward_019ffbcd-1aee-78bf-8f4f-78243e487736" xlink:to="loc_us-gaap_ProvisionForDoubtfulAccounts_019ffbcd-1aee-70f8-9dde-3655a24d806b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableWriteOffs_019ffbcd-1aee-7534-abd2-ff7e6847d3c7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivableWriteOffs"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward_019ffbcd-1aee-78bf-8f4f-78243e487736" xlink:to="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableWriteOffs_019ffbcd-1aee-7534-abd2-ff7e6847d3c7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_AccountsReceivableAllowanceForCreditLossWriteoffNet_019ffbcd-1aee-7948-8c30-0d849e69cec1" xlink:href="knf-20260930.xsd#knf_AccountsReceivableAllowanceForCreditLossWriteoffNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward_019ffbcd-1aee-78bf-8f4f-78243e487736" xlink:to="loc_knf_AccountsReceivableAllowanceForCreditLossWriteoffNet_019ffbcd-1aee-7948-8c30-0d849e69cec1" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsReceivable_019ffbcd-1aee-7ffd-9832-f4452b84a8ca" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivable"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.kniferiver.com/role/RevenuefromContractswithCustomersDetails" xlink:type="simple" xlink:href="knf-20260930.xsd#RevenuefromContractswithCustomersDetails"/>
  <link:definitionLink xlink:role="http://www.kniferiver.com/role/RevenuefromContractswithCustomersDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_019ffbcd-1aee-7c4f-aca5-95104790a26f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_019ffbcd-1aee-755c-b69f-d34025c31188" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisaggregationOfRevenueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019ffbcd-1aee-7c4f-aca5-95104790a26f" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_019ffbcd-1aee-755c-b69f-d34025c31188" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_019ffbcd-1aee-78b6-aba1-dbc6e37db644" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_019ffbcd-1aee-755c-b69f-d34025c31188" xlink:to="loc_srt_ProductOrServiceAxis_019ffbcd-1aee-78b6-aba1-dbc6e37db644" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019ffbcd-1aee-78b6-aba1-dbc6e37db644_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_019ffbcd-1aee-78b6-aba1-dbc6e37db644" xlink:to="loc_srt_ProductsAndServicesDomain_019ffbcd-1aee-78b6-aba1-dbc6e37db644_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019ffbcd-1aee-7de6-8c58-9261dd89b9d4" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_019ffbcd-1aee-78b6-aba1-dbc6e37db644" xlink:to="loc_srt_ProductsAndServicesDomain_019ffbcd-1aee-7de6-8c58-9261dd89b9d4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_AggregatesMember_019ffbcd-1aee-742b-8529-d66c9da3757d" xlink:href="knf-20260930.xsd#knf_AggregatesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019ffbcd-1aee-7de6-8c58-9261dd89b9d4" xlink:to="loc_knf_AggregatesMember_019ffbcd-1aee-742b-8529-d66c9da3757d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_ReadyMixConcreteMember_019ffbcd-1aee-7dc3-85f8-0310a50cacb1" xlink:href="knf-20260930.xsd#knf_ReadyMixConcreteMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019ffbcd-1aee-7de6-8c58-9261dd89b9d4" xlink:to="loc_knf_ReadyMixConcreteMember_019ffbcd-1aee-7dc3-85f8-0310a50cacb1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_AsphaltMember_019ffbcd-1aee-7a3b-80b8-7194c83207aa" xlink:href="knf-20260930.xsd#knf_AsphaltMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019ffbcd-1aee-7de6-8c58-9261dd89b9d4" xlink:to="loc_knf_AsphaltMember_019ffbcd-1aee-7a3b-80b8-7194c83207aa" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_LiquidAsphaltMember_019ffbcd-1aee-7eb2-9e30-ab2b72e32e02" xlink:href="knf-20260930.xsd#knf_LiquidAsphaltMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019ffbcd-1aee-7de6-8c58-9261dd89b9d4" xlink:to="loc_knf_LiquidAsphaltMember_019ffbcd-1aee-7eb2-9e30-ab2b72e32e02" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_OtherMember_019ffbcd-1aee-7046-b46d-0f26e10687e0" xlink:href="knf-20260930.xsd#knf_OtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019ffbcd-1aee-7de6-8c58-9261dd89b9d4" xlink:to="loc_knf_OtherMember_019ffbcd-1aee-7046-b46d-0f26e10687e0" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_ContractingServicesPublicSectorMember_019ffbcd-1aee-7de2-8bdd-2ed3d8867149" xlink:href="knf-20260930.xsd#knf_ContractingServicesPublicSectorMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019ffbcd-1aee-7de6-8c58-9261dd89b9d4" xlink:to="loc_knf_ContractingServicesPublicSectorMember_019ffbcd-1aee-7de2-8bdd-2ed3d8867149" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_ContractingServicesPrivateSectorMember_019ffbcd-1aee-77a3-8a3f-6e74be97c239" xlink:href="knf-20260930.xsd#knf_ContractingServicesPrivateSectorMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019ffbcd-1aee-7de6-8c58-9261dd89b9d4" xlink:to="loc_knf_ContractingServicesPrivateSectorMember_019ffbcd-1aee-77a3-8a3f-6e74be97c239" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_019ffbcd-1aee-7b7b-bdf1-5b946b750f0d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_019ffbcd-1aee-755c-b69f-d34025c31188" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_019ffbcd-1aee-7b7b-bdf1-5b946b750f0d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019ffbcd-1aee-7b7b-bdf1-5b946b750f0d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019ffbcd-1aee-7b7b-bdf1-5b946b750f0d" xlink:to="loc_us-gaap_SegmentDomain_019ffbcd-1aee-7b7b-bdf1-5b946b750f0d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019ffbcd-1aee-71f9-a3d2-48ffe32828e7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019ffbcd-1aee-7b7b-bdf1-5b946b750f0d" xlink:to="loc_us-gaap_SegmentDomain_019ffbcd-1aee-71f9-a3d2-48ffe32828e7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_WestSegmentMember_019ffbcd-1aee-7e64-806b-9c612a100240" xlink:href="knf-20260930.xsd#knf_WestSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019ffbcd-1aee-71f9-a3d2-48ffe32828e7" xlink:to="loc_knf_WestSegmentMember_019ffbcd-1aee-7e64-806b-9c612a100240" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_MountainSegmentMember_019ffbcd-1aee-717a-8ccc-63049ef2cf22" xlink:href="knf-20260930.xsd#knf_MountainSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019ffbcd-1aee-71f9-a3d2-48ffe32828e7" xlink:to="loc_knf_MountainSegmentMember_019ffbcd-1aee-717a-8ccc-63049ef2cf22" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_CentralSegmentMember_019ffbcd-1aee-7288-8a5f-611ddeab6a03" xlink:href="knf-20260930.xsd#knf_CentralSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019ffbcd-1aee-71f9-a3d2-48ffe32828e7" xlink:to="loc_knf_CentralSegmentMember_019ffbcd-1aee-7288-8a5f-611ddeab6a03" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_EnergyServicesSegmentMember_019ffbcd-1aee-7c1e-a555-3e1682f2df8e" xlink:href="knf-20260930.xsd#knf_EnergyServicesSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019ffbcd-1aee-71f9-a3d2-48ffe32828e7" xlink:to="loc_knf_EnergyServicesSegmentMember_019ffbcd-1aee-7c1e-a555-3e1682f2df8e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_CorporateServicesSegmentMember_019ffbcd-1aee-730b-8af1-cce7ef826474" xlink:href="knf-20260930.xsd#knf_CorporateServicesSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019ffbcd-1aee-71f9-a3d2-48ffe32828e7" xlink:to="loc_knf_CorporateServicesSegmentMember_019ffbcd-1aee-730b-8af1-cce7ef826474" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_019ffbcd-1aee-7021-80b3-90adb9b65637" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_019ffbcd-1aee-755c-b69f-d34025c31188" xlink:to="loc_srt_ConsolidationItemsAxis_019ffbcd-1aee-7021-80b3-90adb9b65637" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_019ffbcd-1aee-7021-80b3-90adb9b65637_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_019ffbcd-1aee-7021-80b3-90adb9b65637" xlink:to="loc_srt_ConsolidationItemsDomain_019ffbcd-1aee-7021-80b3-90adb9b65637_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_019ffbcd-1aee-7eb8-b866-79a0f78f2478" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_019ffbcd-1aee-7021-80b3-90adb9b65637" xlink:to="loc_srt_ConsolidationItemsDomain_019ffbcd-1aee-7eb8-b866-79a0f78f2478" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationEliminationsMember_019ffbcd-1aee-7fc8-81d6-08fed3f8327c" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationEliminationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_019ffbcd-1aee-7eb8-b866-79a0f78f2478" xlink:to="loc_srt_ConsolidationEliminationsMember_019ffbcd-1aee-7fc8-81d6-08fed3f8327c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_OperatingSegmentsExcludingIntersegmentEliminationMember_019ffbcd-1aee-7640-8023-719b8555983d" xlink:href="knf-20260930.xsd#knf_OperatingSegmentsExcludingIntersegmentEliminationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_019ffbcd-1aee-7eb8-b866-79a0f78f2478" xlink:to="loc_knf_OperatingSegmentsExcludingIntersegmentEliminationMember_019ffbcd-1aee-7640-8023-719b8555983d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_ConsolidationAndEliminationAxis_019ffbcd-1aee-78ca-b162-ec2cc23451ab" xlink:href="knf-20260930.xsd#knf_ConsolidationAndEliminationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_019ffbcd-1aee-755c-b69f-d34025c31188" xlink:to="loc_knf_ConsolidationAndEliminationAxis_019ffbcd-1aee-78ca-b162-ec2cc23451ab" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_ConsolidationAndEliminationDomain_019ffbcd-1aee-78ca-b162-ec2cc23451ab_default" xlink:href="knf-20260930.xsd#knf_ConsolidationAndEliminationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_knf_ConsolidationAndEliminationAxis_019ffbcd-1aee-78ca-b162-ec2cc23451ab" xlink:to="loc_knf_ConsolidationAndEliminationDomain_019ffbcd-1aee-78ca-b162-ec2cc23451ab_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_ConsolidationAndEliminationDomain_019ffbcd-1aee-797f-9d60-5471d8d93705" xlink:href="knf-20260930.xsd#knf_ConsolidationAndEliminationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_knf_ConsolidationAndEliminationAxis_019ffbcd-1aee-78ca-b162-ec2cc23451ab" xlink:to="loc_knf_ConsolidationAndEliminationDomain_019ffbcd-1aee-797f-9d60-5471d8d93705" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_CorporateNonSegmentIntersegmentEliminationsMember_019ffbcd-1aee-7852-ba58-282a77c77ee6" xlink:href="knf-20260930.xsd#knf_CorporateNonSegmentIntersegmentEliminationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_knf_ConsolidationAndEliminationDomain_019ffbcd-1aee-797f-9d60-5471d8d93705" xlink:to="loc_knf_CorporateNonSegmentIntersegmentEliminationsMember_019ffbcd-1aee-7852-ba58-282a77c77ee6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_019ffbcd-1aee-7a80-a304-088cfd903812" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019ffbcd-1aee-7c4f-aca5-95104790a26f" xlink:to="loc_us-gaap_Revenues_019ffbcd-1aee-7a80-a304-088cfd903812" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.kniferiver.com/role/UncompletedContractsNarrativeDetails" xlink:type="simple" xlink:href="knf-20260930.xsd#UncompletedContractsNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.kniferiver.com/role/UncompletedContractsNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019ffbcd-1aee-7854-9533-5672d666b74c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_019ffbcd-1aee-7277-9226-3d93888f0f3e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019ffbcd-1aee-7854-9533-5672d666b74c" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_019ffbcd-1aee-7277-9226-3d93888f0f3e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis_019ffbcd-1aee-7805-ace9-df6a702822dc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_019ffbcd-1aee-7277-9226-3d93888f0f3e" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis_019ffbcd-1aee-7805-ace9-df6a702822dc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_019ffbcd-1aee-722e-8a03-25a17ad130be" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_019ffbcd-1aee-7277-9226-3d93888f0f3e" xlink:to="loc_srt_RangeAxis_019ffbcd-1aee-722e-8a03-25a17ad130be" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019ffbcd-1aee-722e-8a03-25a17ad130be_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_019ffbcd-1aee-722e-8a03-25a17ad130be" xlink:to="loc_srt_RangeMember_019ffbcd-1aee-722e-8a03-25a17ad130be_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019ffbcd-1aee-7441-a84a-f2ff7486bcf1" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_019ffbcd-1aee-722e-8a03-25a17ad130be" xlink:to="loc_srt_RangeMember_019ffbcd-1aee-7441-a84a-f2ff7486bcf1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_019ffbcd-1aee-7af7-9642-fb639fb410db" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019ffbcd-1aee-7441-a84a-f2ff7486bcf1" xlink:to="loc_srt_MinimumMember_019ffbcd-1aee-7af7-9642-fb639fb410db" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_019ffbcd-1aee-7a13-9f61-c07347367980" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019ffbcd-1aee-7441-a84a-f2ff7486bcf1" xlink:to="loc_srt_MaximumMember_019ffbcd-1aee-7a13-9f61-c07347367980" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_RevenueDescriptionOfTimingAxis_019ffbcd-1aee-7b32-b269-9502992e1291" xlink:href="knf-20260930.xsd#knf_RevenueDescriptionOfTimingAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_019ffbcd-1aee-7277-9226-3d93888f0f3e" xlink:to="loc_knf_RevenueDescriptionOfTimingAxis_019ffbcd-1aee-7b32-b269-9502992e1291" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_RevenueDescriptionOfTimingDomain_019ffbcd-1aee-7b32-b269-9502992e1291_default" xlink:href="knf-20260930.xsd#knf_RevenueDescriptionOfTimingDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_knf_RevenueDescriptionOfTimingAxis_019ffbcd-1aee-7b32-b269-9502992e1291" xlink:to="loc_knf_RevenueDescriptionOfTimingDomain_019ffbcd-1aee-7b32-b269-9502992e1291_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_RevenueDescriptionOfTimingDomain_019ffbcd-1aee-79af-a8f7-757c44dc3644" xlink:href="knf-20260930.xsd#knf_RevenueDescriptionOfTimingDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_knf_RevenueDescriptionOfTimingAxis_019ffbcd-1aee-7b32-b269-9502992e1291" xlink:to="loc_knf_RevenueDescriptionOfTimingDomain_019ffbcd-1aee-79af-a8f7-757c44dc3644" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_RevenueDescriptionOfTiming12MonthsMember_019ffbcd-1aee-7e89-af7b-e1580f877540" xlink:href="knf-20260930.xsd#knf_RevenueDescriptionOfTiming12MonthsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_knf_RevenueDescriptionOfTimingDomain_019ffbcd-1aee-79af-a8f7-757c44dc3644" xlink:to="loc_knf_RevenueDescriptionOfTiming12MonthsMember_019ffbcd-1aee-7e89-af7b-e1580f877540" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_RevenueDescriptionOfTiming13To24MonthsMember_019ffbcd-1aee-73d4-a4dd-faa4d4913e64" xlink:href="knf-20260930.xsd#knf_RevenueDescriptionOfTiming13To24MonthsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_knf_RevenueDescriptionOfTimingDomain_019ffbcd-1aee-79af-a8f7-757c44dc3644" xlink:to="loc_knf_RevenueDescriptionOfTiming13To24MonthsMember_019ffbcd-1aee-73d4-a4dd-faa4d4913e64" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_RevenueDescriptionOfTiming25MonthsOrMoreMember_019ffbcd-1aee-7691-a2d4-09b555b04e69" xlink:href="knf-20260930.xsd#knf_RevenueDescriptionOfTiming25MonthsOrMoreMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_knf_RevenueDescriptionOfTimingDomain_019ffbcd-1aee-79af-a8f7-757c44dc3644" xlink:to="loc_knf_RevenueDescriptionOfTiming25MonthsOrMoreMember_019ffbcd-1aee-7691-a2d4-09b555b04e69" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityRevenueRecognized_019ffbcd-1aee-7495-9a0f-709c23945b5d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ContractWithCustomerLiabilityRevenueRecognized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019ffbcd-1aee-7854-9533-5672d666b74c" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityRevenueRecognized_019ffbcd-1aee-7495-9a0f-709c23945b5d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerPerformanceObligationSatisfiedInPreviousPeriod_019ffbcd-1aee-7960-8974-ea3c45f7ed6d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ContractWithCustomerPerformanceObligationSatisfiedInPreviousPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019ffbcd-1aee-7854-9533-5672d666b74c" xlink:to="loc_us-gaap_ContractWithCustomerPerformanceObligationSatisfiedInPreviousPeriod_019ffbcd-1aee-7960-8974-ea3c45f7ed6d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligation_019ffbcd-1aee-7184-bfd9-7851943596fe" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueRemainingPerformanceObligation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019ffbcd-1aee-7854-9533-5672d666b74c" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligation_019ffbcd-1aee-7184-bfd9-7851943596fe" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_019ffbcd-1aee-718d-8fdf-07fa6aaf441f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019ffbcd-1aee-7854-9533-5672d666b74c" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_019ffbcd-1aee-718d-8fdf-07fa6aaf441f" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.kniferiver.com/role/UncompletedContractsNarrativeDetails_1" xlink:type="simple" xlink:href="knf-20260930.xsd#UncompletedContractsNarrativeDetails_1"/>
  <link:definitionLink xlink:role="http://www.kniferiver.com/role/UncompletedContractsNarrativeDetails_1" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019ffbcd-1aee-7854-9533-5672d666b74c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_019ffbcd-1aee-7277-9226-3d93888f0f3e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019ffbcd-1aee-7854-9533-5672d666b74c" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_019ffbcd-1aee-7277-9226-3d93888f0f3e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_019ffbcd-1aee-722e-8a03-25a17ad130be" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_019ffbcd-1aee-7277-9226-3d93888f0f3e" xlink:to="loc_srt_RangeAxis_019ffbcd-1aee-722e-8a03-25a17ad130be" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019ffbcd-1aee-722e-8a03-25a17ad130be_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_019ffbcd-1aee-722e-8a03-25a17ad130be" xlink:to="loc_srt_RangeMember_019ffbcd-1aee-722e-8a03-25a17ad130be_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019ffbcd-1aee-7441-a84a-f2ff7486bcf1" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_019ffbcd-1aee-722e-8a03-25a17ad130be" xlink:to="loc_srt_RangeMember_019ffbcd-1aee-7441-a84a-f2ff7486bcf1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_019ffbcd-1aee-7af7-9642-fb639fb410db" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019ffbcd-1aee-7441-a84a-f2ff7486bcf1" xlink:to="loc_srt_MinimumMember_019ffbcd-1aee-7af7-9642-fb639fb410db" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_019ffbcd-1aee-7a13-9f61-c07347367980" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019ffbcd-1aee-7441-a84a-f2ff7486bcf1" xlink:to="loc_srt_MaximumMember_019ffbcd-1aee-7a13-9f61-c07347367980" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_RevenueDescriptionOfTimingAxis_019ffbcd-1aee-7b32-b269-9502992e1291" xlink:href="knf-20260930.xsd#knf_RevenueDescriptionOfTimingAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_019ffbcd-1aee-7277-9226-3d93888f0f3e" xlink:to="loc_knf_RevenueDescriptionOfTimingAxis_019ffbcd-1aee-7b32-b269-9502992e1291" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_RevenueDescriptionOfTimingDomain_019ffbcd-1aee-7b32-b269-9502992e1291_default" xlink:href="knf-20260930.xsd#knf_RevenueDescriptionOfTimingDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_knf_RevenueDescriptionOfTimingAxis_019ffbcd-1aee-7b32-b269-9502992e1291" xlink:to="loc_knf_RevenueDescriptionOfTimingDomain_019ffbcd-1aee-7b32-b269-9502992e1291_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_RevenueDescriptionOfTimingDomain_019ffbcd-1aee-79af-a8f7-757c44dc3644" xlink:href="knf-20260930.xsd#knf_RevenueDescriptionOfTimingDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_knf_RevenueDescriptionOfTimingAxis_019ffbcd-1aee-7b32-b269-9502992e1291" xlink:to="loc_knf_RevenueDescriptionOfTimingDomain_019ffbcd-1aee-79af-a8f7-757c44dc3644" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_RevenueDescriptionOfTiming12MonthsMember_019ffbcd-1aee-7e89-af7b-e1580f877540" xlink:href="knf-20260930.xsd#knf_RevenueDescriptionOfTiming12MonthsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_knf_RevenueDescriptionOfTimingDomain_019ffbcd-1aee-79af-a8f7-757c44dc3644" xlink:to="loc_knf_RevenueDescriptionOfTiming12MonthsMember_019ffbcd-1aee-7e89-af7b-e1580f877540" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_RevenueDescriptionOfTiming13To24MonthsMember_019ffbcd-1aee-73d4-a4dd-faa4d4913e64" xlink:href="knf-20260930.xsd#knf_RevenueDescriptionOfTiming13To24MonthsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_knf_RevenueDescriptionOfTimingDomain_019ffbcd-1aee-79af-a8f7-757c44dc3644" xlink:to="loc_knf_RevenueDescriptionOfTiming13To24MonthsMember_019ffbcd-1aee-73d4-a4dd-faa4d4913e64" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_RevenueDescriptionOfTiming25MonthsOrMoreMember_019ffbcd-1aee-7691-a2d4-09b555b04e69" xlink:href="knf-20260930.xsd#knf_RevenueDescriptionOfTiming25MonthsOrMoreMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_knf_RevenueDescriptionOfTimingDomain_019ffbcd-1aee-79af-a8f7-757c44dc3644" xlink:to="loc_knf_RevenueDescriptionOfTiming25MonthsOrMoreMember_019ffbcd-1aee-7691-a2d4-09b555b04e69" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityRevenueRecognized_019ffbcd-1aee-7495-9a0f-709c23945b5d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ContractWithCustomerLiabilityRevenueRecognized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019ffbcd-1aee-7854-9533-5672d666b74c" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityRevenueRecognized_019ffbcd-1aee-7495-9a0f-709c23945b5d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerPerformanceObligationSatisfiedInPreviousPeriod_019ffbcd-1aee-7960-8974-ea3c45f7ed6d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ContractWithCustomerPerformanceObligationSatisfiedInPreviousPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019ffbcd-1aee-7854-9533-5672d666b74c" xlink:to="loc_us-gaap_ContractWithCustomerPerformanceObligationSatisfiedInPreviousPeriod_019ffbcd-1aee-7960-8974-ea3c45f7ed6d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligation_019ffbcd-1aee-7184-bfd9-7851943596fe" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueRemainingPerformanceObligation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019ffbcd-1aee-7854-9533-5672d666b74c" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligation_019ffbcd-1aee-7184-bfd9-7851943596fe" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_019ffbcd-1aee-718d-8fdf-07fa6aaf441f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019ffbcd-1aee-7854-9533-5672d666b74c" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_019ffbcd-1aee-718d-8fdf-07fa6aaf441f" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.kniferiver.com/role/AcquisitionsandDispositionsDetails" xlink:type="simple" xlink:href="knf-20260930.xsd#AcquisitionsandDispositionsDetails"/>
  <link:definitionLink xlink:role="http://www.kniferiver.com/role/AcquisitionsandDispositionsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_019ffbcd-1aee-71ee-abc4-cabe527d9d63" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019ffbcd-1aee-7458-8595-bed523840177" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019ffbcd-1aee-71ee-abc4-cabe527d9d63" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019ffbcd-1aee-7458-8595-bed523840177" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_019ffbcd-1aee-7f35-83a6-215358f4e072" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019ffbcd-1aee-7458-8595-bed523840177" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_019ffbcd-1aee-7f35-83a6-215358f4e072" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019ffbcd-1aee-7f35-83a6-215358f4e072_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_019ffbcd-1aee-7f35-83a6-215358f4e072" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019ffbcd-1aee-7f35-83a6-215358f4e072_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019ffbcd-1aee-7dba-9277-87cf300b953f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_019ffbcd-1aee-7f35-83a6-215358f4e072" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019ffbcd-1aee-7dba-9277-87cf300b953f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_A2026AggregateAcquisitionsMember_019ffbcd-1aee-7849-96e1-ba49f8be6db5" xlink:href="knf-20260930.xsd#knf_A2026AggregateAcquisitionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019ffbcd-1aee-7dba-9277-87cf300b953f" xlink:to="loc_knf_A2026AggregateAcquisitionsMember_019ffbcd-1aee-7849-96e1-ba49f8be6db5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_MontanaAggregateBasedOperationsMember_019ffbcd-1aee-70ae-aa73-2f95716fdfc2" xlink:href="knf-20260930.xsd#knf_MontanaAggregateBasedOperationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_knf_A2026AggregateAcquisitionsMember_019ffbcd-1aee-7849-96e1-ba49f8be6db5" xlink:to="loc_knf_MontanaAggregateBasedOperationsMember_019ffbcd-1aee-70ae-aa73-2f95716fdfc2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_MontanaReadyMixConcreteBusinessMember_019ffbcd-1aee-7e30-a318-6fc656d1aa29" xlink:href="knf-20260930.xsd#knf_MontanaReadyMixConcreteBusinessMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_knf_A2026AggregateAcquisitionsMember_019ffbcd-1aee-7849-96e1-ba49f8be6db5" xlink:to="loc_knf_MontanaReadyMixConcreteBusinessMember_019ffbcd-1aee-7e30-a318-6fc656d1aa29" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_OregonSupplierOfAggregatesAsphaltContractingAndPavingServicesMember_019ffbcd-1aee-7b8d-bcf3-de16e4342820" xlink:href="knf-20260930.xsd#knf_OregonSupplierOfAggregatesAsphaltContractingAndPavingServicesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_knf_A2026AggregateAcquisitionsMember_019ffbcd-1aee-7849-96e1-ba49f8be6db5" xlink:to="loc_knf_OregonSupplierOfAggregatesAsphaltContractingAndPavingServicesMember_019ffbcd-1aee-7b8d-bcf3-de16e4342820" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_A2025AggregateAcquisitionsMember_019ffbcd-1aee-7f75-b992-9ad915b21777" xlink:href="knf-20260930.xsd#knf_A2025AggregateAcquisitionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019ffbcd-1aee-7dba-9277-87cf300b953f" xlink:to="loc_knf_A2025AggregateAcquisitionsMember_019ffbcd-1aee-7f75-b992-9ad915b21777" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationAxis_019ffbcd-1aee-74dc-abe4-5326b11d1580" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupClassificationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019ffbcd-1aee-7458-8595-bed523840177" xlink:to="loc_us-gaap_DisposalGroupClassificationAxis_019ffbcd-1aee-74dc-abe4-5326b11d1580" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_019ffbcd-1aee-74dc-abe4-5326b11d1580_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupClassificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_019ffbcd-1aee-74dc-abe4-5326b11d1580" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_019ffbcd-1aee-74dc-abe4-5326b11d1580_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_019ffbcd-1aee-7313-9272-728e1f417217" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupClassificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_019ffbcd-1aee-74dc-abe4-5326b11d1580" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_019ffbcd-1aee-7313-9272-728e1f417217" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DiscontinuedOperationsDisposedOfBySaleMember_019ffbcd-1aee-74dc-9ea4-ec170fa952a8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DiscontinuedOperationsDisposedOfBySaleMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupClassificationDomain_019ffbcd-1aee-7313-9272-728e1f417217" xlink:to="loc_us-gaap_DiscontinuedOperationsDisposedOfBySaleMember_019ffbcd-1aee-74dc-9ea4-ec170fa952a8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_019ffbcd-1aee-74f7-8917-7a33082cc111" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019ffbcd-1aee-7458-8595-bed523840177" xlink:to="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_019ffbcd-1aee-74f7-8917-7a33082cc111" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_019ffbcd-1aee-74f7-8917-7a33082cc111_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_019ffbcd-1aee-74f7-8917-7a33082cc111" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_019ffbcd-1aee-74f7-8917-7a33082cc111_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_019ffbcd-1aee-77f0-a5f6-136719d388cf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_019ffbcd-1aee-74f7-8917-7a33082cc111" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_019ffbcd-1aee-77f0-a5f6-136719d388cf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_StrataReadyMixPlantOperationsMember_019ffbcd-1aee-76df-bf60-333b636e84e3" xlink:href="knf-20260930.xsd#knf_StrataReadyMixPlantOperationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_019ffbcd-1aee-77f0-a5f6-136719d388cf" xlink:to="loc_knf_StrataReadyMixPlantOperationsMember_019ffbcd-1aee-76df-bf60-333b636e84e3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfBusinessesAcquired_019ffbcd-1aee-714a-8bb8-fe68bb15ee1b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NumberOfBusinessesAcquired"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019ffbcd-1aee-71ee-abc4-cabe527d9d63" xlink:to="loc_us-gaap_NumberOfBusinessesAcquired_019ffbcd-1aee-714a-8bb8-fe68bb15ee1b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationBargainPurchaseGainRecognizedAmount_019ffbcd-1aee-7111-9122-8789bb38c1da" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationBargainPurchaseGainRecognizedAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019ffbcd-1aee-71ee-abc4-cabe527d9d63" xlink:to="loc_us-gaap_BusinessCombinationBargainPurchaseGainRecognizedAmount_019ffbcd-1aee-7111-9122-8789bb38c1da" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_01a18f08-b256-78ce-bb22-bfc03bfc20b7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019ffbcd-1aee-71ee-abc4-cabe527d9d63" xlink:to="loc_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_01a18f08-b256-78ce-bb22-bfc03bfc20b7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssets_019ffbcd-1aee-7a99-88e7-6927d15a8ec4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019ffbcd-1aee-71ee-abc4-cabe527d9d63" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssets_019ffbcd-1aee-7a99-88e7-6927d15a8ec4" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment_019ffbcd-1aee-7c59-8668-dec27e3cbb8f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019ffbcd-1aee-71ee-abc4-cabe527d9d63" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment_019ffbcd-1aee-7c59-8668-dec27e3cbb8f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_019ffbcd-1aee-7463-b9d2-82b28b8a87ec" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019ffbcd-1aee-71ee-abc4-cabe527d9d63" xlink:to="loc_us-gaap_Goodwill_019ffbcd-1aee-7463-b9d2-82b28b8a87ec" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles_019ffbcd-1aee-7684-b366-42bf1d1ec443" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019ffbcd-1aee-71ee-abc4-cabe527d9d63" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles_019ffbcd-1aee-7684-b366-42bf1d1ec443" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxLiabilities_019ffbcd-1aee-73c8-bdce-bcd9b0498dd8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019ffbcd-1aee-71ee-abc4-cabe527d9d63" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxLiabilities_019ffbcd-1aee-73c8-bdce-bcd9b0498dd8" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilities_019ffbcd-1aee-7133-859d-819a6ae98450" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019ffbcd-1aee-71ee-abc4-cabe527d9d63" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilities_019ffbcd-1aee-7133-859d-819a6ae98450" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther_019ffbcd-1aee-7ce8-af87-a3a2139d99aa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019ffbcd-1aee-71ee-abc4-cabe527d9d63" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther_019ffbcd-1aee-7ce8-af87-a3a2139d99aa" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillPurchaseAccountingAdjustments_019ffbcd-1aee-7bed-993c-3f72660ae3b5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GoodwillPurchaseAccountingAdjustments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019ffbcd-1aee-71ee-abc4-cabe527d9d63" xlink:to="loc_us-gaap_GoodwillPurchaseAccountingAdjustments_019ffbcd-1aee-7bed-993c-3f72660ae3b5" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationProFormaInformationRevenueOfAcquireeSinceAcquisitionDateActual_019ffbcd-1aee-75f3-a6c1-0cc42975177f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationProFormaInformationRevenueOfAcquireeSinceAcquisitionDateActual"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019ffbcd-1aee-71ee-abc4-cabe527d9d63" xlink:to="loc_us-gaap_BusinessCombinationProFormaInformationRevenueOfAcquireeSinceAcquisitionDateActual_019ffbcd-1aee-75f3-a6c1-0cc42975177f" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationProFormaInformationEarningsOrLossOfAcquireeSinceAcquisitionDateActual_019ffbcd-1aee-7af3-8f1a-2e4d645f85e0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationProFormaInformationEarningsOrLossOfAcquireeSinceAcquisitionDateActual"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019ffbcd-1aee-71ee-abc4-cabe527d9d63" xlink:to="loc_us-gaap_BusinessCombinationProFormaInformationEarningsOrLossOfAcquireeSinceAcquisitionDateActual_019ffbcd-1aee-7af3-8f1a-2e4d645f85e0" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferred1_019ffbcd-1aee-7d3d-84e1-6da856691eda" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationConsiderationTransferred1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019ffbcd-1aee-71ee-abc4-cabe527d9d63" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferred1_019ffbcd-1aee-7d3d-84e1-6da856691eda" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentIntangibles_019ffbcd-1aee-7349-9a57-3df8a1fd6449" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentIntangibles"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019ffbcd-1aee-71ee-abc4-cabe527d9d63" xlink:to="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentIntangibles_019ffbcd-1aee-7349-9a57-3df8a1fd6449" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentPropertyPlantAndEquipment_019ffbcd-1aee-72aa-b35e-ece51377e2d0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentPropertyPlantAndEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019ffbcd-1aee-71ee-abc4-cabe527d9d63" xlink:to="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentPropertyPlantAndEquipment_019ffbcd-1aee-72aa-b35e-ece51377e2d0" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_BusinessCombinationConsiderationTransferredHoldbackPayment_01a19ba8-661e-7fba-b930-0d8d2e883ce1" xlink:href="knf-20260930.xsd#knf_BusinessCombinationConsiderationTransferredHoldbackPayment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019ffbcd-1aee-71ee-abc4-cabe527d9d63" xlink:to="loc_knf_BusinessCombinationConsiderationTransferredHoldbackPayment_01a19ba8-661e-7fba-b930-0d8d2e883ce1" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationAcquisitionRelatedCosts_019ffbcd-1aee-72fc-9670-f65ae1f3477f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationAcquisitionRelatedCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019ffbcd-1aee-71ee-abc4-cabe527d9d63" xlink:to="loc_us-gaap_BusinessCombinationAcquisitionRelatedCosts_019ffbcd-1aee-72fc-9670-f65ae1f3477f" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_DisposalGroupIncludingDiscontinuedOperationNumberOfPlantOperationsSold_019ffbcd-1aee-797b-bdd1-ae44e1efbe1f" xlink:href="knf-20260930.xsd#knf_DisposalGroupIncludingDiscontinuedOperationNumberOfPlantOperationsSold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019ffbcd-1aee-71ee-abc4-cabe527d9d63" xlink:to="loc_knf_DisposalGroupIncludingDiscontinuedOperationNumberOfPlantOperationsSold_019ffbcd-1aee-797b-bdd1-ae44e1efbe1f" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromDivestitureOfBusinesses_019ffbcd-1aee-71b6-942d-efe53706deeb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromDivestitureOfBusinesses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019ffbcd-1aee-71ee-abc4-cabe527d9d63" xlink:to="loc_us-gaap_ProceedsFromDivestitureOfBusinesses_019ffbcd-1aee-71b6-942d-efe53706deeb" xlink:type="arc" order="19"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.kniferiver.com/role/GoodwillandOtherIntangibleAssetsScheduleofChangesintheCarryingAmountofGoodwillDetails" xlink:type="simple" xlink:href="knf-20260930.xsd#GoodwillandOtherIntangibleAssetsScheduleofChangesintheCarryingAmountofGoodwillDetails"/>
  <link:definitionLink xlink:role="http://www.kniferiver.com/role/GoodwillandOtherIntangibleAssetsScheduleofChangesintheCarryingAmountofGoodwillDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillLineItems_019ffbcd-1aee-7dbf-b897-ddf309dc490b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GoodwillLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfGoodwillTable_019ffbcd-1aee-7e1b-a05f-d9aafe3ee366" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfGoodwillTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_GoodwillLineItems_019ffbcd-1aee-7dbf-b897-ddf309dc490b" xlink:to="loc_us-gaap_ScheduleOfGoodwillTable_019ffbcd-1aee-7e1b-a05f-d9aafe3ee366" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_019ffbcd-1aee-75fd-b5af-aae4b6119a7c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_019ffbcd-1aee-7e1b-a05f-d9aafe3ee366" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_019ffbcd-1aee-75fd-b5af-aae4b6119a7c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019ffbcd-1aee-75fd-b5af-aae4b6119a7c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019ffbcd-1aee-75fd-b5af-aae4b6119a7c" xlink:to="loc_us-gaap_SegmentDomain_019ffbcd-1aee-75fd-b5af-aae4b6119a7c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019ffbcd-1aee-77f7-b25e-72403287dd24" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019ffbcd-1aee-75fd-b5af-aae4b6119a7c" xlink:to="loc_us-gaap_SegmentDomain_019ffbcd-1aee-77f7-b25e-72403287dd24" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_WestSegmentMember_019ffbcd-1aee-7c59-9c64-a9b3a56dec65" xlink:href="knf-20260930.xsd#knf_WestSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019ffbcd-1aee-77f7-b25e-72403287dd24" xlink:to="loc_knf_WestSegmentMember_019ffbcd-1aee-7c59-9c64-a9b3a56dec65" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_MountainSegmentMember_019ffbcd-1aee-726c-8ec9-38083635bb3f" xlink:href="knf-20260930.xsd#knf_MountainSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019ffbcd-1aee-77f7-b25e-72403287dd24" xlink:to="loc_knf_MountainSegmentMember_019ffbcd-1aee-726c-8ec9-38083635bb3f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_CentralSegmentMember_019ffbcd-1aee-7d02-be08-267fbb6b690f" xlink:href="knf-20260930.xsd#knf_CentralSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019ffbcd-1aee-77f7-b25e-72403287dd24" xlink:to="loc_knf_CentralSegmentMember_019ffbcd-1aee-7d02-be08-267fbb6b690f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_EnergyServicesSegmentMember_019ffbcd-1aee-7626-983a-18b4ad3e9c08" xlink:href="knf-20260930.xsd#knf_EnergyServicesSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019ffbcd-1aee-77f7-b25e-72403287dd24" xlink:to="loc_knf_EnergyServicesSegmentMember_019ffbcd-1aee-7626-983a-18b4ad3e9c08" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillRollForward_019ffbcd-1aee-77d5-8b28-3e6672b1a49a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GoodwillRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_019ffbcd-1aee-7dbf-b897-ddf309dc490b" xlink:to="loc_us-gaap_GoodwillRollForward_019ffbcd-1aee-77d5-8b28-3e6672b1a49a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_019ffbcd-1aee-7338-a71d-f231e206e33e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillRollForward_019ffbcd-1aee-77d5-8b28-3e6672b1a49a" xlink:to="loc_us-gaap_Goodwill_019ffbcd-1aee-7338-a71d-f231e206e33e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillAcquiredDuringPeriod_019ffbcd-1aee-70b5-a5eb-3a1c0064c926" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GoodwillAcquiredDuringPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillRollForward_019ffbcd-1aee-77d5-8b28-3e6672b1a49a" xlink:to="loc_us-gaap_GoodwillAcquiredDuringPeriod_019ffbcd-1aee-70b5-a5eb-3a1c0064c926" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillPurchaseAccountingAdjustments_019ffbcd-1aee-77d2-a59e-0b0231c2e351" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GoodwillPurchaseAccountingAdjustments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillRollForward_019ffbcd-1aee-77d5-8b28-3e6672b1a49a" xlink:to="loc_us-gaap_GoodwillPurchaseAccountingAdjustments_019ffbcd-1aee-77d2-a59e-0b0231c2e351" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_019ffbcd-1aee-7c68-9703-a98573e99744" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Goodwill"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.kniferiver.com/role/GoodwillandOtherIntangibleAssetsScheduleofOtherAmortizableIntangibleAssetsDetails" xlink:type="simple" xlink:href="knf-20260930.xsd#GoodwillandOtherIntangibleAssetsScheduleofOtherAmortizableIntangibleAssetsDetails"/>
  <link:definitionLink xlink:role="http://www.kniferiver.com/role/GoodwillandOtherIntangibleAssetsScheduleofOtherAmortizableIntangibleAssetsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_019ffbcd-1aee-71ab-bea6-1c64480ddabc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_019ffbcd-1aee-792e-bef6-1734f0cac4af" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_019ffbcd-1aee-71ab-bea6-1c64480ddabc" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_019ffbcd-1aee-792e-bef6-1734f0cac4af" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019ffbcd-1aee-7e47-9505-1618eba4d859" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_019ffbcd-1aee-792e-bef6-1734f0cac4af" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019ffbcd-1aee-7e47-9505-1618eba4d859" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019ffbcd-1aee-7e47-9505-1618eba4d859_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019ffbcd-1aee-7e47-9505-1618eba4d859" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019ffbcd-1aee-7e47-9505-1618eba4d859_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019ffbcd-1aee-72d7-9eaa-51ec581b7550" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019ffbcd-1aee-7e47-9505-1618eba4d859" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019ffbcd-1aee-72d7-9eaa-51ec581b7550" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerRelationshipsMember_019ffbcd-1aee-7087-a348-52ef472aa4a6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CustomerRelationshipsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019ffbcd-1aee-72d7-9eaa-51ec581b7550" xlink:to="loc_us-gaap_CustomerRelationshipsMember_019ffbcd-1aee-7087-a348-52ef472aa4a6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncompeteAgreementsMember_019ffbcd-1aee-782c-8485-4b0ce01f1497" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NoncompeteAgreementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019ffbcd-1aee-72d7-9eaa-51ec581b7550" xlink:to="loc_us-gaap_NoncompeteAgreementsMember_019ffbcd-1aee-782c-8485-4b0ce01f1497" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TradeNamesMember_019ffbcd-1aee-7702-9982-18655481e2b6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TradeNamesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019ffbcd-1aee-72d7-9eaa-51ec581b7550" xlink:to="loc_us-gaap_TradeNamesMember_019ffbcd-1aee-7702-9982-18655481e2b6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OrderOrProductionBacklogMember_019ffbcd-1aee-768d-a2c9-3dd1384bbcbd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OrderOrProductionBacklogMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019ffbcd-1aee-72d7-9eaa-51ec581b7550" xlink:to="loc_us-gaap_OrderOrProductionBacklogMember_019ffbcd-1aee-768d-a2c9-3dd1384bbcbd" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherIntangibleAssetsMember_019ffbcd-1aee-768b-be05-21af41d30573" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherIntangibleAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019ffbcd-1aee-72d7-9eaa-51ec581b7550" xlink:to="loc_us-gaap_OtherIntangibleAssetsMember_019ffbcd-1aee-768b-be05-21af41d30573" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsGross_019ffbcd-1aee-7448-8014-63e79d004dde" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_019ffbcd-1aee-71ab-bea6-1c64480ddabc" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsGross_019ffbcd-1aee-7448-8014-63e79d004dde" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_019ffbcd-1aee-7f82-9924-b2533ea79f7e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_019ffbcd-1aee-71ab-bea6-1c64480ddabc" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_019ffbcd-1aee-7f82-9924-b2533ea79f7e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_019ffbcd-1aee-7dd4-a419-e98571a44583" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_019ffbcd-1aee-71ab-bea6-1c64480ddabc" xlink:to="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_019ffbcd-1aee-7dd4-a419-e98571a44583" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.kniferiver.com/role/FairValueMeasurementsScheduleofAssetsMeasuredatFairValueonaRecurringBasisDetails" xlink:type="simple" xlink:href="knf-20260930.xsd#FairValueMeasurementsScheduleofAssetsMeasuredatFairValueonaRecurringBasisDetails"/>
  <link:definitionLink xlink:role="http://www.kniferiver.com/role/FairValueMeasurementsScheduleofAssetsMeasuredatFairValueonaRecurringBasisDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019ffbcd-1aee-7571-8cad-fcd08741adf9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019ffbcd-1aee-757e-9012-29119785eaa5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019ffbcd-1aee-7571-8cad-fcd08741adf9" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019ffbcd-1aee-757e-9012-29119785eaa5" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019ffbcd-1aee-7252-b8a7-6a953d7c35ca" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019ffbcd-1aee-757e-9012-29119785eaa5" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019ffbcd-1aee-7252-b8a7-6a953d7c35ca" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019ffbcd-1aee-7252-b8a7-6a953d7c35ca_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019ffbcd-1aee-7252-b8a7-6a953d7c35ca" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019ffbcd-1aee-7252-b8a7-6a953d7c35ca_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019ffbcd-1aee-7038-b4e6-2deefe5ff374" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019ffbcd-1aee-7252-b8a7-6a953d7c35ca" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019ffbcd-1aee-7038-b4e6-2deefe5ff374" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_019ffbcd-1aee-79e5-a1de-7fc0206c74a5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019ffbcd-1aee-7038-b4e6-2deefe5ff374" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_019ffbcd-1aee-79e5-a1de-7fc0206c74a5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_019ffbcd-1aee-7163-ae37-aa5657a6d157" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019ffbcd-1aee-7038-b4e6-2deefe5ff374" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_019ffbcd-1aee-7163-ae37-aa5657a6d157" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_019ffbcd-1aee-7965-945e-b968726f8c5e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019ffbcd-1aee-7038-b4e6-2deefe5ff374" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_019ffbcd-1aee-7965-945e-b968726f8c5e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_019ffbcd-1aee-76e1-9a46-e13c5ed12f86" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019ffbcd-1aee-757e-9012-29119785eaa5" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_019ffbcd-1aee-76e1-9a46-e13c5ed12f86" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_019ffbcd-1aee-76e1-9a46-e13c5ed12f86_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_019ffbcd-1aee-76e1-9a46-e13c5ed12f86" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_019ffbcd-1aee-76e1-9a46-e13c5ed12f86_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_019ffbcd-1aee-79f8-9a9b-4c94b13d746a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_019ffbcd-1aee-76e1-9a46-e13c5ed12f86" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_019ffbcd-1aee-79f8-9a9b-4c94b13d746a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_019ffbcd-1aee-70f4-b9e9-d0fb8172541c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsRecurringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_019ffbcd-1aee-79f8-9a9b-4c94b13d746a" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_019ffbcd-1aee-70f4-b9e9-d0fb8172541c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MoneyMarketFundsAtCarryingValue_019ffbcd-1aee-7c1c-98b6-d135744cf324" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MoneyMarketFundsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019ffbcd-1aee-7571-8cad-fcd08741adf9" xlink:to="loc_us-gaap_MoneyMarketFundsAtCarryingValue_019ffbcd-1aee-7c1c-98b6-d135744cf324" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashSurrenderValueFairValueDisclosure_019ffbcd-1aee-71e7-9399-87e56cb24319" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashSurrenderValueFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019ffbcd-1aee-7571-8cad-fcd08741adf9" xlink:to="loc_us-gaap_CashSurrenderValueFairValueDisclosure_019ffbcd-1aee-71e7-9399-87e56cb24319" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosure_019ffbcd-1aee-7f1c-ab56-da22baff0b9f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019ffbcd-1aee-7571-8cad-fcd08741adf9" xlink:to="loc_us-gaap_AssetsFairValueDisclosure_019ffbcd-1aee-7f1c-ab56-da22baff0b9f" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.kniferiver.com/role/FairValueMeasurementsScheduleofFairValueofLongTermDebtDetails" xlink:type="simple" xlink:href="knf-20260930.xsd#FairValueMeasurementsScheduleofFairValueofLongTermDebtDetails"/>
  <link:definitionLink xlink:role="http://www.kniferiver.com/role/FairValueMeasurementsScheduleofFairValueofLongTermDebtDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019ffbcd-1aee-7f84-ac77-f8e2c9df20f4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTable_019ffbcd-1aee-73f6-b5e9-cab367146d14" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByBalanceSheetGroupingTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019ffbcd-1aee-7f84-ac77-f8e2c9df20f4" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingTable_019ffbcd-1aee-73f6-b5e9-cab367146d14" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementBasisAxis_019ffbcd-1aee-7cba-91a1-6d7b125664ff" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByMeasurementBasisAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_019ffbcd-1aee-73f6-b5e9-cab367146d14" xlink:to="loc_us-gaap_FairValueByMeasurementBasisAxis_019ffbcd-1aee-7cba-91a1-6d7b125664ff" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019ffbcd-1aee-7cba-91a1-6d7b125664ff_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_019ffbcd-1aee-7cba-91a1-6d7b125664ff" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019ffbcd-1aee-7cba-91a1-6d7b125664ff_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosureItemAmountsDomain_019ffbcd-1aee-7ff3-ac1e-acdbf02d223b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueDisclosureItemAmountsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_019ffbcd-1aee-7cba-91a1-6d7b125664ff" xlink:to="loc_us-gaap_FairValueDisclosureItemAmountsDomain_019ffbcd-1aee-7ff3-ac1e-acdbf02d223b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019ffbcd-1aee-72ae-8273-33dc1730b2e1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_019ffbcd-1aee-7ff3-ac1e-acdbf02d223b" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019ffbcd-1aee-72ae-8273-33dc1730b2e1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_019ffbcd-1aee-777d-b496-c5670d18d3d8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CarryingReportedAmountFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019ffbcd-1aee-72ae-8273-33dc1730b2e1" xlink:to="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_019ffbcd-1aee-777d-b496-c5670d18d3d8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_019ffbcd-1aee-7f65-bdb1-55ec07858394" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019ffbcd-1aee-72ae-8273-33dc1730b2e1" xlink:to="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_019ffbcd-1aee-7f65-bdb1-55ec07858394" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtFairValue_019ffbcd-1aee-7782-99c2-7d55e75ee77b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019ffbcd-1aee-7f84-ac77-f8e2c9df20f4" xlink:to="loc_us-gaap_LongTermDebtFairValue_019ffbcd-1aee-7782-99c2-7d55e75ee77b" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.kniferiver.com/role/DebtNarrativeDetails" xlink:type="simple" xlink:href="knf-20260930.xsd#DebtNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.kniferiver.com/role/DebtNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_019ffbcd-1aee-7ef9-af2f-e80b1d9d4f54" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_019ffbcd-1aee-7b9c-94b6-fbb649589a54" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019ffbcd-1aee-7ef9-af2f-e80b1d9d4f54" xlink:to="loc_us-gaap_DebtInstrumentTable_019ffbcd-1aee-7b9c-94b6-fbb649589a54" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_019ffbcd-1aee-7506-b705-19aaece964da" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019ffbcd-1aee-7b9c-94b6-fbb649589a54" xlink:to="loc_us-gaap_DebtInstrumentAxis_019ffbcd-1aee-7506-b705-19aaece964da" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019ffbcd-1aee-7506-b705-19aaece964da_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_019ffbcd-1aee-7506-b705-19aaece964da" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019ffbcd-1aee-7506-b705-19aaece964da_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019ffbcd-1aee-7be0-8076-c96b3a80213f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_019ffbcd-1aee-7506-b705-19aaece964da" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019ffbcd-1aee-7be0-8076-c96b3a80213f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_A5.74TermLoanAgreementDue2032Member_019ffbcd-1aee-75cf-a381-5f77daffabf4" xlink:href="knf-20260930.xsd#knf_A5.74TermLoanAgreementDue2032Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019ffbcd-1aee-7be0-8076-c96b3a80213f" xlink:to="loc_knf_A5.74TermLoanAgreementDue2032Member_019ffbcd-1aee-75cf-a381-5f77daffabf4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_019ffbcd-1aee-74a6-975b-320aef16e98a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019ffbcd-1aee-7b9c-94b6-fbb649589a54" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_019ffbcd-1aee-74a6-975b-320aef16e98a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019ffbcd-1aee-74a6-975b-320aef16e98a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019ffbcd-1aee-74a6-975b-320aef16e98a" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019ffbcd-1aee-74a6-975b-320aef16e98a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019ffbcd-1aee-78a6-bd6a-74a2c34b71d6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019ffbcd-1aee-74a6-975b-320aef16e98a" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019ffbcd-1aee-78a6-bd6a-74a2c34b71d6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_019ffbcd-1aee-7c36-9b0d-6102720814fd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019ffbcd-1aee-78a6-bd6a-74a2c34b71d6" xlink:to="loc_us-gaap_LineOfCreditMember_019ffbcd-1aee-7c36-9b0d-6102720814fd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_LineOfCreditFacilityMaximumBorrowingCapacityIncrease_019ffbcd-1aee-7408-b60f-541a7ec3ad8f" xlink:href="knf-20260930.xsd#knf_LineOfCreditFacilityMaximumBorrowingCapacityIncrease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019ffbcd-1aee-7ef9-af2f-e80b1d9d4f54" xlink:to="loc_knf_LineOfCreditFacilityMaximumBorrowingCapacityIncrease_019ffbcd-1aee-7408-b60f-541a7ec3ad8f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateIncreaseDecrease_019ffbcd-1aee-7562-b1a8-8893710bc377" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentInterestRateIncreaseDecrease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019ffbcd-1aee-7ef9-af2f-e80b1d9d4f54" xlink:to="loc_us-gaap_DebtInstrumentInterestRateIncreaseDecrease_019ffbcd-1aee-7562-b1a8-8893710bc377" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_019ffbcd-1aee-73ef-9c27-f22cf0062f46" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019ffbcd-1aee-7ef9-af2f-e80b1d9d4f54" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_019ffbcd-1aee-73ef-9c27-f22cf0062f46" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_DebtInstrumentCovenantMandatoryAnnualAmortization_019ffbcd-1aee-755c-9b34-4e140f7daba3" xlink:href="knf-20260930.xsd#knf_DebtInstrumentCovenantMandatoryAnnualAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019ffbcd-1aee-7ef9-af2f-e80b1d9d4f54" xlink:to="loc_knf_DebtInstrumentCovenantMandatoryAnnualAmortization_019ffbcd-1aee-755c-9b34-4e140f7daba3" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.kniferiver.com/role/DebtScheduleofLongTermDebtOutstandingDetails" xlink:type="simple" xlink:href="knf-20260930.xsd#DebtScheduleofLongTermDebtOutstandingDetails"/>
  <link:definitionLink xlink:role="http://www.kniferiver.com/role/DebtScheduleofLongTermDebtOutstandingDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_019ffbcd-1aee-7f10-ace5-51673c87e6ed" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_019ffbcd-1aee-77da-8544-4b5604d4684b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019ffbcd-1aee-7f10-ace5-51673c87e6ed" xlink:to="loc_us-gaap_DebtInstrumentTable_019ffbcd-1aee-77da-8544-4b5604d4684b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_019ffbcd-1aee-7902-94be-48561ef46d2f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019ffbcd-1aee-77da-8544-4b5604d4684b" xlink:to="loc_us-gaap_DebtInstrumentAxis_019ffbcd-1aee-7902-94be-48561ef46d2f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019ffbcd-1aee-7902-94be-48561ef46d2f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_019ffbcd-1aee-7902-94be-48561ef46d2f" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019ffbcd-1aee-7902-94be-48561ef46d2f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019ffbcd-1aee-7d68-9a4b-b3260ca2cccc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_019ffbcd-1aee-7902-94be-48561ef46d2f" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019ffbcd-1aee-7d68-9a4b-b3260ca2cccc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_A5.42TermLoanAgreementDue2030Member_019ffbcd-1aee-77eb-9c01-c4e7bf146ec2" xlink:href="knf-20260930.xsd#knf_A5.42TermLoanAgreementDue2030Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019ffbcd-1aee-7d68-9a4b-b3260ca2cccc" xlink:to="loc_knf_A5.42TermLoanAgreementDue2030Member_019ffbcd-1aee-77eb-9c01-c4e7bf146ec2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_A5.74TermLoanAgreementDue2032Member_019ffbcd-1aee-7970-997e-8d5662b44ac1" xlink:href="knf-20260930.xsd#knf_A5.74TermLoanAgreementDue2032Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019ffbcd-1aee-7d68-9a4b-b3260ca2cccc" xlink:to="loc_knf_A5.74TermLoanAgreementDue2032Member_019ffbcd-1aee-7970-997e-8d5662b44ac1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_A7.75SeniorNotesDue2031Member_019ffbcd-1aee-719f-9afd-2f1f42538c23" xlink:href="knf-20260930.xsd#knf_A7.75SeniorNotesDue2031Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019ffbcd-1aee-7d68-9a4b-b3260ca2cccc" xlink:to="loc_knf_A7.75SeniorNotesDue2031Member_019ffbcd-1aee-719f-9afd-2f1f42538c23" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_OtherNotesDue2061Member_019ffbcd-1aee-7400-92d6-9350cdef5925" xlink:href="knf-20260930.xsd#knf_OtherNotesDue2061Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019ffbcd-1aee-7d68-9a4b-b3260ca2cccc" xlink:to="loc_knf_OtherNotesDue2061Member_019ffbcd-1aee-7400-92d6-9350cdef5925" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_019ffbcd-1aee-7440-beaf-36376c853634" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019ffbcd-1aee-77da-8544-4b5604d4684b" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_019ffbcd-1aee-7440-beaf-36376c853634" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019ffbcd-1aee-7440-beaf-36376c853634_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019ffbcd-1aee-7440-beaf-36376c853634" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019ffbcd-1aee-7440-beaf-36376c853634_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019ffbcd-1aee-76a2-b7d2-91ef3f8afd99" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019ffbcd-1aee-7440-beaf-36376c853634" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019ffbcd-1aee-76a2-b7d2-91ef3f8afd99" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_019ffbcd-1aee-74dd-9702-77ab364a5345" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019ffbcd-1aee-76a2-b7d2-91ef3f8afd99" xlink:to="loc_us-gaap_LineOfCreditMember_019ffbcd-1aee-74dd-9702-77ab364a5345" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotesMember_019ffbcd-1aee-73f3-a0d7-59e218218c2b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SeniorNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019ffbcd-1aee-76a2-b7d2-91ef3f8afd99" xlink:to="loc_us-gaap_SeniorNotesMember_019ffbcd-1aee-73f3-a0d7-59e218218c2b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesPayableOtherPayablesMember_019ffbcd-1aee-72de-8069-2eeae2f7d7ae" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NotesPayableOtherPayablesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019ffbcd-1aee-76a2-b7d2-91ef3f8afd99" xlink:to="loc_us-gaap_NotesPayableOtherPayablesMember_019ffbcd-1aee-72de-8069-2eeae2f7d7ae" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtWeightedAverageInterestRate_019ffbcd-1aee-7053-a074-87a6cdda99ac" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtWeightedAverageInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019ffbcd-1aee-7f10-ace5-51673c87e6ed" xlink:to="loc_us-gaap_LongtermDebtWeightedAverageInterestRate_019ffbcd-1aee-7053-a074-87a6cdda99ac" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_019ffbcd-1aee-7e9e-af6c-be9402078996" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019ffbcd-1aee-7f10-ace5-51673c87e6ed" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_019ffbcd-1aee-7e9e-af6c-be9402078996" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFinanceCostsNet_019ffbcd-1aee-743a-affe-61d4b152715d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredFinanceCostsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019ffbcd-1aee-7f10-ace5-51673c87e6ed" xlink:to="loc_us-gaap_DeferredFinanceCostsNet_019ffbcd-1aee-743a-affe-61d4b152715d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_019ffbcd-1aee-7084-ad65-b60832fa83fd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019ffbcd-1aee-7f10-ace5-51673c87e6ed" xlink:to="loc_us-gaap_LongTermDebt_019ffbcd-1aee-7084-ad65-b60832fa83fd" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtCurrent_019ffbcd-1aee-7547-bbac-549a1a198863" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019ffbcd-1aee-7f10-ace5-51673c87e6ed" xlink:to="loc_us-gaap_LongTermDebtCurrent_019ffbcd-1aee-7547-bbac-549a1a198863" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtNoncurrent_019ffbcd-1aee-7c92-a7d0-fcae7d9cbb2d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019ffbcd-1aee-7f10-ace5-51673c87e6ed" xlink:to="loc_us-gaap_LongTermDebtNoncurrent_019ffbcd-1aee-7c92-a7d0-fcae7d9cbb2d" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.kniferiver.com/role/BusinessSegmentDataScheduleofSegmentReportingInformationbySegmentDetails" xlink:type="simple" xlink:href="knf-20260930.xsd#BusinessSegmentDataScheduleofSegmentReportingInformationbySegmentDetails"/>
  <link:definitionLink xlink:role="http://www.kniferiver.com/role/BusinessSegmentDataScheduleofSegmentReportingInformationbySegmentDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_019ffbcd-1b9a-7994-a531-95627b9845f7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019ffbcd-1b9a-7b4a-a202-275f066ebc33" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019ffbcd-1b9a-7994-a531-95627b9845f7" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019ffbcd-1b9a-7b4a-a202-275f066ebc33" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_019ffbcd-1b9a-7cd6-b431-b81c5375f61a" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019ffbcd-1b9a-7b4a-a202-275f066ebc33" xlink:to="loc_srt_ConsolidationItemsAxis_019ffbcd-1b9a-7cd6-b431-b81c5375f61a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_019ffbcd-1b9a-7cd6-b431-b81c5375f61a_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_019ffbcd-1b9a-7cd6-b431-b81c5375f61a" xlink:to="loc_srt_ConsolidationItemsDomain_019ffbcd-1b9a-7cd6-b431-b81c5375f61a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_019ffbcd-1b9a-77fe-94af-896f58ea44a4" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_019ffbcd-1b9a-7cd6-b431-b81c5375f61a" xlink:to="loc_srt_ConsolidationItemsDomain_019ffbcd-1b9a-77fe-94af-896f58ea44a4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_OperatingSegmentsExcludingIntersegmentEliminationMember_019ffbcd-1b9a-7d54-85ba-e7b6f9fca187" xlink:href="knf-20260930.xsd#knf_OperatingSegmentsExcludingIntersegmentEliminationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_019ffbcd-1b9a-77fe-94af-896f58ea44a4" xlink:to="loc_knf_OperatingSegmentsExcludingIntersegmentEliminationMember_019ffbcd-1b9a-7d54-85ba-e7b6f9fca187" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntersegmentEliminationMember_019ffbcd-1b9a-7450-af42-b7aa82043fab" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IntersegmentEliminationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_019ffbcd-1b9a-77fe-94af-896f58ea44a4" xlink:to="loc_us-gaap_IntersegmentEliminationMember_019ffbcd-1b9a-7450-af42-b7aa82043fab" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingSegmentsMember_019ffbcd-1b9a-74a5-8a53-51b0d296d38e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_019ffbcd-1b9a-77fe-94af-896f58ea44a4" xlink:to="loc_us-gaap_OperatingSegmentsMember_019ffbcd-1b9a-74a5-8a53-51b0d296d38e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateNonSegmentMember_019ffbcd-1b9a-7f34-872b-0f5532415b8d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CorporateNonSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_019ffbcd-1b9a-77fe-94af-896f58ea44a4" xlink:to="loc_us-gaap_CorporateNonSegmentMember_019ffbcd-1b9a-7f34-872b-0f5532415b8d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_EliminationsAndReconcilingItemsMember_019ffbcd-1b9a-7d0c-a869-682f8d8ef236" xlink:href="knf-20260930.xsd#knf_EliminationsAndReconcilingItemsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_019ffbcd-1b9a-77fe-94af-896f58ea44a4" xlink:to="loc_knf_EliminationsAndReconcilingItemsMember_019ffbcd-1b9a-7d0c-a869-682f8d8ef236" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationEliminationsMember_019ffbcd-1b9a-7a2e-ad8f-1b064d65ac52" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationEliminationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_019ffbcd-1b9a-77fe-94af-896f58ea44a4" xlink:to="loc_srt_ConsolidationEliminationsMember_019ffbcd-1b9a-7a2e-ad8f-1b064d65ac52" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_019ffbcd-1b9a-7733-90db-602259d4774a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019ffbcd-1b9a-7b4a-a202-275f066ebc33" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_019ffbcd-1b9a-7733-90db-602259d4774a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019ffbcd-1b9a-7733-90db-602259d4774a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019ffbcd-1b9a-7733-90db-602259d4774a" xlink:to="loc_us-gaap_SegmentDomain_019ffbcd-1b9a-7733-90db-602259d4774a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019ffbcd-1b9a-79a1-a517-862cc713ed49" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019ffbcd-1b9a-7733-90db-602259d4774a" xlink:to="loc_us-gaap_SegmentDomain_019ffbcd-1b9a-79a1-a517-862cc713ed49" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_WestSegmentMember_019ffbcd-1b9a-7e18-981b-72b7661f376a" xlink:href="knf-20260930.xsd#knf_WestSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019ffbcd-1b9a-79a1-a517-862cc713ed49" xlink:to="loc_knf_WestSegmentMember_019ffbcd-1b9a-7e18-981b-72b7661f376a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_MountainSegmentMember_019ffbcd-1b9a-745f-b515-ba749a0df315" xlink:href="knf-20260930.xsd#knf_MountainSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019ffbcd-1b9a-79a1-a517-862cc713ed49" xlink:to="loc_knf_MountainSegmentMember_019ffbcd-1b9a-745f-b515-ba749a0df315" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_CentralSegmentMember_019ffbcd-1b9a-7ab0-ae9b-5b367a0a39a8" xlink:href="knf-20260930.xsd#knf_CentralSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019ffbcd-1b9a-79a1-a517-862cc713ed49" xlink:to="loc_knf_CentralSegmentMember_019ffbcd-1b9a-7ab0-ae9b-5b367a0a39a8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_EnergyServicesSegmentMember_019ffbcd-1b9a-744d-8d62-84295b4da34d" xlink:href="knf-20260930.xsd#knf_EnergyServicesSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019ffbcd-1b9a-79a1-a517-862cc713ed49" xlink:to="loc_knf_EnergyServicesSegmentMember_019ffbcd-1b9a-744d-8d62-84295b4da34d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesAxis_019ffbcd-1b9a-73d5-b601-8649576134dd" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidatedEntitiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019ffbcd-1b9a-7b4a-a202-275f066ebc33" xlink:to="loc_srt_ConsolidatedEntitiesAxis_019ffbcd-1b9a-73d5-b601-8649576134dd" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_019ffbcd-1b9a-73d5-b601-8649576134dd_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidatedEntitiesAxis_019ffbcd-1b9a-73d5-b601-8649576134dd" xlink:to="loc_srt_ConsolidatedEntitiesDomain_019ffbcd-1b9a-73d5-b601-8649576134dd_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_019ffbcd-1b9a-7c0c-9d88-b13b5c813fdb" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidatedEntitiesAxis_019ffbcd-1b9a-73d5-b601-8649576134dd" xlink:to="loc_srt_ConsolidatedEntitiesDomain_019ffbcd-1b9a-7c0c-9d88-b13b5c813fdb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ParentMember_019ffbcd-1b9a-75ec-8737-51a2a1af2c3c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ParentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidatedEntitiesDomain_019ffbcd-1b9a-7c0c-9d88-b13b5c813fdb" xlink:to="loc_us-gaap_ParentMember_019ffbcd-1b9a-75ec-8737-51a2a1af2c3c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_019ffbcd-1b9a-7d18-99e6-7d61e358284d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019ffbcd-1b9a-7994-a531-95627b9845f7" xlink:to="loc_us-gaap_Revenues_019ffbcd-1b9a-7d18-99e6-7d61e358284d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfGoodsAndServiceExcludingDepreciationDepletionAndAmortization_019ffbcd-1b9a-782a-bc8a-426e693d31f1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CostOfGoodsAndServiceExcludingDepreciationDepletionAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019ffbcd-1b9a-7994-a531-95627b9845f7" xlink:to="loc_us-gaap_CostOfGoodsAndServiceExcludingDepreciationDepletionAndAmortization_019ffbcd-1b9a-782a-bc8a-426e693d31f1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpense_019ffbcd-1b9a-735e-9254-48abe1ce70a3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SellingGeneralAndAdministrativeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019ffbcd-1b9a-7994-a531-95627b9845f7" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpense_019ffbcd-1b9a-735e-9254-48abe1ce70a3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingOtherItemAmount_019ffbcd-1b9a-7c04-8d07-4caae9809bb5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentReportingOtherItemAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019ffbcd-1b9a-7994-a531-95627b9845f7" xlink:to="loc_us-gaap_SegmentReportingOtherItemAmount_019ffbcd-1b9a-7c04-8d07-4caae9809bb5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019ffbcd-1b9a-7dc4-8d07-4444b2e05019" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019ffbcd-1b9a-7994-a531-95627b9845f7" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019ffbcd-1b9a-7dc4-8d07-4444b2e05019" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationDepletionAndAmortization_019ffbcd-1b9a-7f07-8832-3043c14ce048" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DepreciationDepletionAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019ffbcd-1b9a-7994-a531-95627b9845f7" xlink:to="loc_us-gaap_DepreciationDepletionAndAmortization_019ffbcd-1b9a-7f07-8832-3043c14ce048" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeExpenseNonoperatingNet_019ffbcd-1b9a-7235-911a-5c383febb038" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestIncomeExpenseNonoperatingNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019ffbcd-1b9a-7994-a531-95627b9845f7" xlink:to="loc_us-gaap_InterestIncomeExpenseNonoperatingNet_019ffbcd-1b9a-7235-911a-5c383febb038" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherIncome_019ffbcd-1b9a-7046-9195-559eb2e977d6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019ffbcd-1b9a-7994-a531-95627b9845f7" xlink:to="loc_us-gaap_OtherIncome_019ffbcd-1b9a-7046-9195-559eb2e977d6" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherExpenses_019ffbcd-1b9a-7431-b61b-cbee607126e1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherExpenses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019ffbcd-1b9a-7994-a531-95627b9845f7" xlink:to="loc_us-gaap_OtherExpenses_019ffbcd-1b9a-7431-b61b-cbee607126e1" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_EarningsBeforeInterestTaxDepreciationAndAmortization_019ffbcd-1b9a-76ea-9963-cbfd218d3849" xlink:href="knf-20260930.xsd#knf_EarningsBeforeInterestTaxDepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019ffbcd-1b9a-7994-a531-95627b9845f7" xlink:to="loc_knf_EarningsBeforeInterestTaxDepreciationAndAmortization_019ffbcd-1b9a-76ea-9963-cbfd218d3849" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentExpenditureAdditionToLongLivedAssets_019ffbcd-1b9a-79f2-903f-5e5917f1cb25" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentExpenditureAdditionToLongLivedAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019ffbcd-1b9a-7994-a531-95627b9845f7" xlink:to="loc_us-gaap_SegmentExpenditureAdditionToLongLivedAssets_019ffbcd-1b9a-79f2-903f-5e5917f1cb25" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_019ffbcd-1b9a-74d4-85a1-d11df2c06b2d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Assets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019ffbcd-1b9a-7994-a531-95627b9845f7" xlink:to="loc_us-gaap_Assets_019ffbcd-1b9a-74d4-85a1-d11df2c06b2d" xlink:type="arc" order="11"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.kniferiver.com/role/CommitmentsandContingenciesDetails" xlink:type="simple" xlink:href="knf-20260930.xsd#CommitmentsandContingenciesDetails"/>
  <link:definitionLink xlink:role="http://www.kniferiver.com/role/CommitmentsandContingenciesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesLineItems_019ffbcd-1b9a-7dfd-b118-a4385b69230c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LossContingenciesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesTable_019ffbcd-1b9a-7f49-b84d-ea31ac6835cd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LossContingenciesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LossContingenciesLineItems_019ffbcd-1b9a-7dfd-b118-a4385b69230c" xlink:to="loc_us-gaap_LossContingenciesTable_019ffbcd-1b9a-7f49-b84d-ea31ac6835cd" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_019ffbcd-1b9a-76f8-897c-21e633fb7059" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_019ffbcd-1b9a-7f49-b84d-ea31ac6835cd" xlink:to="loc_us-gaap_CreditFacilityAxis_019ffbcd-1b9a-76f8-897c-21e633fb7059" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_019ffbcd-1b9a-76f8-897c-21e633fb7059_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_019ffbcd-1b9a-76f8-897c-21e633fb7059" xlink:to="loc_us-gaap_CreditFacilityDomain_019ffbcd-1b9a-76f8-897c-21e633fb7059_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_019ffbcd-1b9a-72c1-b009-07c0b84acec4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_019ffbcd-1b9a-76f8-897c-21e633fb7059" xlink:to="loc_us-gaap_CreditFacilityDomain_019ffbcd-1b9a-72c1-b009-07c0b84acec4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LetterOfCreditMember_019ffbcd-1b9a-7315-8eb9-3d09a9c947f9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LetterOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_019ffbcd-1b9a-72c1-b009-07c0b84acec4" xlink:to="loc_us-gaap_LetterOfCreditMember_019ffbcd-1b9a-7315-8eb9-3d09a9c947f9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyAccrualAtCarryingValue_019ffbcd-1b9a-763b-83ea-33bdd45af85d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LossContingencyAccrualAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019ffbcd-1b9a-7dfd-b118-a4385b69230c" xlink:to="loc_us-gaap_LossContingencyAccrualAtCarryingValue_019ffbcd-1b9a-763b-83ea-33bdd45af85d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyReceivable_019ffbcd-1b9a-7656-ace3-6316e212154f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LossContingencyReceivable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019ffbcd-1b9a-7dfd-b118-a4385b69230c" xlink:to="loc_us-gaap_LossContingencyReceivable_019ffbcd-1b9a-7656-ace3-6316e212154f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_LossContingencyNewLawsuitsFiledNumber_019ffbcd-1b9a-7265-b17c-90ee86f3cc25" xlink:href="knf-20260930.xsd#knf_LossContingencyNewLawsuitsFiledNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019ffbcd-1b9a-7dfd-b118-a4385b69230c" xlink:to="loc_knf_LossContingencyNewLawsuitsFiledNumber_019ffbcd-1b9a-7265-b17c-90ee86f3cc25" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsMaximumExposure_019ffbcd-1b9a-7d89-9b39-a640e4f210a2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GuaranteeObligationsMaximumExposure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019ffbcd-1b9a-7dfd-b118-a4385b69230c" xlink:to="loc_us-gaap_GuaranteeObligationsMaximumExposure_019ffbcd-1b9a-7d89-9b39-a640e4f210a2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsCurrentCarryingValue_019ffbcd-1b9a-7487-b9c6-df3299c67240" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GuaranteeObligationsCurrentCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019ffbcd-1b9a-7dfd-b118-a4385b69230c" xlink:to="loc_us-gaap_GuaranteeObligationsCurrentCarryingValue_019ffbcd-1b9a-7487-b9c6-df3299c67240" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_019ffbcd-1b9a-7085-8a53-fb7a242edeb7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019ffbcd-1b9a-7dfd-b118-a4385b69230c" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_019ffbcd-1b9a-7085-8a53-fb7a242edeb7" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_LettersofCreditSettoExpireCurrentYear_019ffbcd-1b9a-7fe7-9ae9-44c8fc0b27e5" xlink:href="knf-20260930.xsd#knf_LettersofCreditSettoExpireCurrentYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019ffbcd-1b9a-7dfd-b118-a4385b69230c" xlink:to="loc_knf_LettersofCreditSettoExpireCurrentYear_019ffbcd-1b9a-7fe7-9ae9-44c8fc0b27e5" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_LettersofCreditSettoExpireinNextFiscalYear_019ffbcd-1b9a-7a87-b60d-9a3f7730ca17" xlink:href="knf-20260930.xsd#knf_LettersofCreditSettoExpireinNextFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019ffbcd-1b9a-7dfd-b118-a4385b69230c" xlink:to="loc_knf_LettersofCreditSettoExpireinNextFiscalYear_019ffbcd-1b9a-7a87-b60d-9a3f7730ca17" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_LettersOfCreditSetToExpireYearTwo_019ffbcd-1b9a-7d6c-a91d-248894b1ad57" xlink:href="knf-20260930.xsd#knf_LettersOfCreditSetToExpireYearTwo"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019ffbcd-1b9a-7dfd-b118-a4385b69230c" xlink:to="loc_knf_LettersOfCreditSetToExpireYearTwo_019ffbcd-1b9a-7d6c-a91d-248894b1ad57" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LettersOfCreditOutstandingAmount_019ffbcd-1b9a-7ff7-8e2b-95e7b05828e6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LettersOfCreditOutstandingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019ffbcd-1b9a-7dfd-b118-a4385b69230c" xlink:to="loc_us-gaap_LettersOfCreditOutstandingAmount_019ffbcd-1b9a-7ff7-8e2b-95e7b05828e6" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_SuretyBondExpirationPeriod_019ffbcd-1b9a-7d03-80f0-7fa2d437402d" xlink:href="knf-20260930.xsd#knf_SuretyBondExpirationPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019ffbcd-1b9a-7dfd-b118-a4385b69230c" xlink:to="loc_knf_SuretyBondExpirationPeriod_019ffbcd-1b9a-7d03-80f0-7fa2d437402d" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_knf_AmountOfSuretyBondsOutstanding_019ffbcd-1b9a-7315-9011-e54afb2ce40a" xlink:href="knf-20260930.xsd#knf_AmountOfSuretyBondsOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019ffbcd-1b9a-7dfd-b118-a4385b69230c" xlink:to="loc_knf_AmountOfSuretyBondsOutstanding_019ffbcd-1b9a-7315-9011-e54afb2ce40a" xlink:type="arc" order="11"/>
  </link:definitionLink>
</link:linkbase>
