Wheel's centre (3)
I believe the answer is:
hub
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">wheel's centre</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for hub that I've seen before include "Wheel's centre" , "Centre of activity" , "Nave of a wheel" , "Focus" , "throbbing heart" .)