Palomino pen (6)
I believe the answer is:
corral
'palomino pen' 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 livestock (US)" , "Famous gunfight at the OK ..... in American West" , "American enclosure for horses" , "Horse enclosure out West" , "Shorten (book)" .)