Circuit of a racetrack (3)
I believe the answer is:
lap
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">circuit of a racetrack</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 lap that I've seen before include "Scoop up with the tongue" , "One round of the course" , "Knees" , "Circuit (of a race track)" , "Thighs, when seated" .)