Sun room (8)
I believe the answer is:
solarium
'sun room' is the definition.
(I know that sun room can be written as solarium)
This is all the clue.
(Other definitions for solarium that I've seen before include "Sun parlour" , "A room with sunlamps for tanning" , "Room for sunbathing" , "Room where people can benefit from exposure to sunlight" , "Room in which people can be exposed to sun or sun-lamps" .)