From sub- + subroutine. <span class="searchmatch">subsubroutine</span> (plural <span class="searchmatch">subsubroutines</span>) (computing, rare) A subroutine called from another subroutine. 1962, Robert Mills Gagné...
<span class="searchmatch">subsubroutines</span> plural of <span class="searchmatch">subsubroutine</span>...