Racetrack circuit (3)
I believe the answer is:
lap
'racetrack circuit' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for lap that I've seen before include "One round of the track" , "Scoop up with the tongue" , "revolution" , "400 metres, typically" , "Use tongue to drink; circuit" .)