Some theatre clearly is place for play (3)
I believe the answer is:
rec
'place for play' is the definition.
(short for recreation ground)
'some theatre clearly is' is the wordplay.
'some' says the answer is hidden in the clue (some of the parts of the word are used).
'REC' is hidden within 'theatre clearly is'.
(Other definitions for rec that I've seen before include "place for outdoor games" , "record" , "pleasure area" , "Recreation ground (informal)" , "play area" .)