Children's play area (7)
I believe the answer is:
sandpit
'children's play area' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for sandpit that I've seen before include "Play area for small children" , "children may play here" , "Excavation for children to play in" , "area for kids to play in" , "place where youngsters can play" .)