<?xml version="1.0" encoding="us-ascii" standalone="yes"?>
<!--XBRL Document Created with XBRLMaster-->
<!--Version: 2.3.08-->
<!--Based on XBRL 2.1-->
<!--Date of creation: 05/13/2026-->
<!--Software architectural design and coding: A'c Dharmapremananda Avt.-->
<!--Copyright (c) 2026 I-NET Business Solutions, Inc. All Rights Reserved.-->
<link:linkbase xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:link="http://www.xbrl.org/2003/linkbase" 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:roleRef roleURI="http://fstj.com/role/Cover" xlink:href="fstj-20260331.xsd#Cover" xlink:type="simple" />
  <link:roleRef roleURI="http://fstj.com/role/CondensedConsolidatedBalanceSheets" xlink:href="fstj-20260331.xsd#CondensedConsolidatedBalanceSheets" xlink:type="simple" />
  <link:roleRef roleURI="http://fstj.com/role/CondensedConsolidatedBalanceSheetsParenthetical" xlink:href="fstj-20260331.xsd#CondensedConsolidatedBalanceSheetsParenthetical" xlink:type="simple" />
  <link:roleRef roleURI="http://fstj.com/role/CondensedConsolidatedStatementsOfOperationsUnaudited" xlink:href="fstj-20260331.xsd#CondensedConsolidatedStatementsOfOperationsUnaudited" xlink:type="simple" />
  <link:roleRef roleURI="http://fstj.com/role/CondensedConsolidatedStatementsOfStockholdersDeficitUnaudited" xlink:href="fstj-20260331.xsd#CondensedConsolidatedStatementsOfStockholdersDeficitUnaudited" xlink:type="simple" />
  <link:roleRef roleURI="http://fstj.com/role/ConsolidatedStatementsOfCashFlows" xlink:href="fstj-20260331.xsd#ConsolidatedStatementsOfCashFlows" xlink:type="simple" />
  <link:roleRef roleURI="http://fstj.com/role/NatureOfTheCompanyAndBusiness" xlink:href="fstj-20260331.xsd#NatureOfTheCompanyAndBusiness" xlink:type="simple" />
  <link:roleRef roleURI="http://fstj.com/role/SummaryOfSignificantAccountingPolicies" xlink:href="fstj-20260331.xsd#SummaryOfSignificantAccountingPolicies" xlink:type="simple" />
  <link:roleRef roleURI="http://fstj.com/role/CommitmentsAndContingencies" xlink:href="fstj-20260331.xsd#CommitmentsAndContingencies" xlink:type="simple" />
  <link:roleRef roleURI="http://fstj.com/role/Concentrations" xlink:href="fstj-20260331.xsd#Concentrations" xlink:type="simple" />
  <link:roleRef roleURI="http://fstj.com/role/RelatedPartyTransactions" xlink:href="fstj-20260331.xsd#RelatedPartyTransactions" xlink:type="simple" />
  <link:roleRef roleURI="http://fstj.com/role/SummaryOfSignificantAccountingPoliciesPolicies" xlink:href="fstj-20260331.xsd#SummaryOfSignificantAccountingPoliciesPolicies" xlink:type="simple" />
  <link:roleRef roleURI="http://fstj.com/role/ConcentrationsTables" xlink:href="fstj-20260331.xsd#ConcentrationsTables" xlink:type="simple" />
  <link:roleRef roleURI="http://fstj.com/role/ConcentrationsDetails" xlink:href="fstj-20260331.xsd#ConcentrationsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://fstj.com/role/ConcentrationsDetails1" xlink:href="fstj-20260331.xsd#ConcentrationsDetails1" xlink:type="simple" />
  <link:roleRef roleURI="http://fstj.com/role/RelatedPartyTransactionsDetailsNarrative" xlink:href="fstj-20260331.xsd#RelatedPartyTransactionsDetailsNarrative" xlink:type="simple" />
  <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension" arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" />
  <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain" arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" />
  <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member" arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" />
  <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" arcroleURI="http://xbrl.org/int/dim/arcrole/all" />
  <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#notAll" arcroleURI="http://xbrl.org/int/dim/arcrole/notAll" />
  <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default" arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" />
  <link:definitionLink xlink:type="extended" xlink:role="http://fstj.com/role/Cover" xlink:title="00000001 - Document - Cover Page Information">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_CoverAbstract" xlink:label="loc_deiCover" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://fstj.com/role/CondensedConsolidatedBalanceSheets" xlink:title="110200 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS" />
  <link:definitionLink xlink:type="extended" xlink:role="http://fstj.com/role/CondensedConsolidatedBalanceSheetsParenthetical" xlink:title="110201 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical)" />
  <link:definitionLink xlink:type="extended" xlink:role="http://fstj.com/role/CondensedConsolidatedStatementsOfOperationsUnaudited" xlink:title="124100 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (UNAUDITED)" />
  <link:definitionLink xlink:type="extended" xlink:role="http://fstj.com/role/CondensedConsolidatedStatementsOfStockholdersDeficitUnaudited" xlink:title="148600 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' DEFICIT (UNAUDITED)">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" order="2000" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaapStatementEquityComponentsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapStatementEquityComponentsAxis" order="1020" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaapEquityComponentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapStatementEquityComponentsAxis" xlink:to="loc_us-gaapEquityComponentDomain" order="1030" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaapEquityComponentDomain_10" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaapStatementEquityComponentsAxis" xlink:to="loc_us-gaapEquityComponentDomain_10" order="1040" xbrldt:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockMember" xlink:label="loc_us-gaapCommonStockMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_us-gaapCommonStockMember" order="1021" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AdditionalPaidInCapitalMember" xlink:label="loc_us-gaapAdditionalPaidInCapitalMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_us-gaapAdditionalPaidInCapitalMember" order="1022" />
    <link:loc xlink:type="locator" xlink:href="fstj-20260331.xsd#fstj_CommonStockMeTechMember" xlink:label="loc_fstjCommonStockMeTechMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_fstjCommonStockMeTechMember" order="1023" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetainedEarningsMember" xlink:label="loc_us-gaapRetainedEarningsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_us-gaapRetainedEarningsMember" order="1024" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SharesIssued" xlink:label="loc_us-gaapSharesIssued" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapSharesIssued" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquity" xlink:label="loc_us-gaapStockholdersEquity" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockholdersEquity" order="2" />
    <link:loc xlink:type="locator" xlink:href="fstj-20260331.xsd#fstj_EffectOfReverseMergerShares" xlink:label="loc_fstjEffectOfReverseMergerShares" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_fstjEffectOfReverseMergerShares" order="3" />
    <link:loc xlink:type="locator" xlink:href="fstj-20260331.xsd#fstj_EffectOfReverseMergerAmount" xlink:label="loc_fstjEffectOfReverseMergerAmount" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_fstjEffectOfReverseMergerAmount" order="4" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaapNetIncomeLoss" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapNetIncomeLoss" order="5" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://fstj.com/role/ConsolidatedStatementsOfCashFlows" xlink:title="170000 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS" />
  <link:definitionLink xlink:type="extended" xlink:role="http://fstj.com/role/NatureOfTheCompanyAndBusiness" xlink:title="995446 - Disclosure - Nature of the Company and Business" />
  <link:definitionLink xlink:type="extended" xlink:role="http://fstj.com/role/SummaryOfSignificantAccountingPolicies" xlink:title="995447 - Disclosure - Summary of Significant Accounting Policies" />
  <link:definitionLink xlink:type="extended" xlink:role="http://fstj.com/role/CommitmentsAndContingencies" xlink:title="995448 - Disclosure - Commitments and Contingencies" />
  <link:definitionLink xlink:type="extended" xlink:role="http://fstj.com/role/Concentrations" xlink:title="995449 - Disclosure - Concentrations" />
  <link:definitionLink xlink:type="extended" xlink:role="http://fstj.com/role/RelatedPartyTransactions" xlink:title="995450 - Disclosure - Related Party Transactions" />
  <link:definitionLink xlink:type="extended" xlink:role="http://fstj.com/role/SummaryOfSignificantAccountingPoliciesPolicies" xlink:title="995451 - Disclosure - Summary of Significant Accounting Policies (Policies)" />
  <link:definitionLink xlink:type="extended" xlink:role="http://fstj.com/role/ConcentrationsTables" xlink:title="995452 - Disclosure - Concentrations (Tables)" />
  <link:definitionLink xlink:type="extended" xlink:role="http://fstj.com/role/ConcentrationsDetails" xlink:title="995453 - Disclosure - Concentrations (Details)">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" order="2000" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskByTypeAxis" xlink:label="loc_us-gaapConcentrationRiskByTypeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapConcentrationRiskByTypeAxis" order="1020" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="loc_us-gaapConcentrationRiskTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapConcentrationRiskByTypeAxis" xlink:to="loc_us-gaapConcentrationRiskTypeDomain" order="1030" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="loc_us-gaapConcentrationRiskTypeDomain_10" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaapConcentrationRiskByTypeAxis" xlink:to="loc_us-gaapConcentrationRiskTypeDomain_10" order="1040" xbrldt:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="fstj-20260331.xsd#fstj_CustomerAMember" xlink:label="loc_fstjCustomerAMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapConcentrationRiskTypeDomain" xlink:to="loc_fstjCustomerAMember" order="1021" />
    <link:loc xlink:type="locator" xlink:href="fstj-20260331.xsd#fstj_CustomerBMember" xlink:label="loc_fstjCustomerBMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapConcentrationRiskTypeDomain" xlink:to="loc_fstjCustomerBMember" order="1022" />
    <link:loc xlink:type="locator" xlink:href="fstj-20260331.xsd#fstj_CustomerCMember" xlink:label="loc_fstjCustomerCMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapConcentrationRiskTypeDomain" xlink:to="loc_fstjCustomerCMember" order="1023" />
    <link:loc xlink:type="locator" xlink:href="fstj-20260331.xsd#fstj_CustomerEMember" xlink:label="loc_fstjCustomerEMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapConcentrationRiskTypeDomain" xlink:to="loc_fstjCustomerEMember" order="1024" />
    <link:loc xlink:type="locator" xlink:href="fstj-20260331.xsd#fstj_CustomerDMember" xlink:label="loc_fstjCustomerDMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapConcentrationRiskTypeDomain" xlink:to="loc_fstjCustomerDMember" order="1025" />
    <link:loc xlink:type="locator" xlink:href="fstj-20260331.xsd#fstj_ConcentrationRiskPercentageRevenue" xlink:label="loc_fstjConcentrationRiskPercentageRevenue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_fstjConcentrationRiskPercentageRevenue" order="1" />
    <link:loc xlink:type="locator" xlink:href="fstj-20260331.xsd#fstj_ConcentrationRiskPercentageOfAccountsReceivable" xlink:label="loc_fstjConcentrationRiskPercentageOfAccountsReceivable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_fstjConcentrationRiskPercentageOfAccountsReceivable" order="2" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://fstj.com/role/ConcentrationsDetails1" xlink:title="995454 - Disclosure - Concentrations (Details 1)">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" order="2000" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskByTypeAxis" xlink:label="loc_us-gaapConcentrationRiskByTypeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapConcentrationRiskByTypeAxis" order="1010" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="loc_us-gaapConcentrationRiskTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapConcentrationRiskByTypeAxis" xlink:to="loc_us-gaapConcentrationRiskTypeDomain" order="1020" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="loc_us-gaapConcentrationRiskTypeDomain_10" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaapConcentrationRiskByTypeAxis" xlink:to="loc_us-gaapConcentrationRiskTypeDomain_10" order="1030" xbrldt:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="fstj-20260331.xsd#fstj_VendorAMember" xlink:label="loc_fstjVendorAMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapConcentrationRiskTypeDomain" xlink:to="loc_fstjVendorAMember" order="1011" />
    <link:loc xlink:type="locator" xlink:href="fstj-20260331.xsd#fstj_ConcentrationRiskPercentageOfRevenue" xlink:label="loc_fstjConcentrationRiskPercentageOfRevenue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_fstjConcentrationRiskPercentageOfRevenue" order="1" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://fstj.com/role/RelatedPartyTransactionsDetailsNarrative" xlink:title="995455 - Disclosure - Related Party Transactions (Details Narrative)">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" order="2000" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" order="1020" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaapRelatedPartyDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:to="loc_us-gaapRelatedPartyDomain" order="1030" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaapRelatedPartyDomain_10" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:to="loc_us-gaapRelatedPartyDomain_10" order="1040" xbrldt:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="fstj-20260331.xsd#fstj_FAMCMember" xlink:label="loc_fstjFAMCMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyDomain" xlink:to="loc_fstjFAMCMember" order="1021" />
    <link:loc xlink:type="locator" xlink:href="fstj-20260331.xsd#fstj_FirstAmericanManagementGroupCorpMember" xlink:label="loc_fstjFirstAmericanManagementGroupCorpMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyDomain" xlink:to="loc_fstjFirstAmericanManagementGroupCorpMember" order="1022" />
    <link:loc xlink:type="locator" xlink:href="fstj-20260331.xsd#fstj_JianLiMember" xlink:label="loc_fstjJianLiMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyDomain" xlink:to="loc_fstjJianLiMember" order="1023" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccountsPayableCurrent" xlink:label="loc_us-gaapAccountsPayableCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapAccountsPayableCurrent" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherExpenses" xlink:label="loc_us-gaapOtherExpenses" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapOtherExpenses" order="2" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccountsReceivableNet" xlink:label="loc_us-gaapAccountsReceivableNet" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapAccountsReceivableNet" order="3" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NotesPayable" xlink:label="loc_us-gaapNotesPayable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapNotesPayable" order="4" />
  </link:definitionLink>
</link:linkbase>
