Enclosed space or room (7)
I believe the answer is:
chamber
I believe this clue is a double definition.
'enclosed space' is the first definition.
(thesaurus)
'room' is the second definition.
(I know that chamber is a type of room)
(Other definitions for chamber that I've seen before include "Judge's room" , "Large room" , "Enclosed cavity, part of gun" , "in which to get the bullet?" , "vault" .)