Front of a semi
I believe the answer is:
cab
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">front of a semi</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for cab that I've seen before include "Hired car" , "A taxi in America" , "Transport" , "Driver's compartment, in lorry say" , "An American taxi" .)