Living room seat (4)
I believe the answer is:
'living room seat' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for sofa that I've seen before include "Long upholstered seat with back and arms" , "Item of furniture" , "Upholstered seat for two or more" , "Upholstered seating" , "Wide padded seat" .)