Pocket to hold a watch (3)
I believe the answer is:
fob
'pocket to hold a watch' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for fob that I've seen before include "Waistcoat pocket" , "Kind of watch on a chain" , "Key-ring tab" , "Chain attached to watch" , "Kind of watch carried in pocket" .)