Frame (7)
I believe the answer is:
chassis
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">frame</span>' is the definition.<br/ ><span class="explanation-format__explanation">(base frame of a vehicle)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for chassis that I've seen before include "Base-frame of car" , "Car framework" , "Vehicle's structure" , "Body framework" , "Vehicle's structural frame" .)