Straps for horses -- some were in stable (5)
I believe the answer is:
reins
'straps for horses' is the definition.
'reins' can be an answer for 'straps' (reins are straps attached to horses). I'm not sure about the 'for horses' bit.
'some were in stable' is the wordplay.
'some' indicates the answer is hidden within the clue (some parts of the word are used).
'REINS' is hidden within 'were in stable'.
Can you help me to learn more?
(Other definitions for reins that I've seen before include "They're used to control" , "Means of checking" , "Guiding straps" , "Rider's straps" , "Control for horses" .)