Where players play in front of play's players, perhaps (9,3)
I believe the answer is:
orchestra pit
'where players play in front of play's' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
'players perhaps' is the wordplay.
'players' becomes 'orchestra' (group playing music).
'perhaps' becomes 'pit' (I can't justify this - if you can you should give a lot more credence to this answer).
'orchestra'+'pit'='ORCHESTRA PIT'
Can you help me to learn more?
(Other definitions for orchestra pit that I've seen before include "Part of a theatre" , "wind down in one" , "Place for theatre musicians" , "Sunken area for theatre musicians" , "space for musicians" .)