Where to hold your horses (6)
I believe the answer is:
corral
'where to hold your horses' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for corral that I've seen before include "Pen for cattle in the US" , "Pen for livestock (US)" , "American enclosure for horses" , "Famous gunfight at the OK ..... in American West" , "Round up" .)