Block of flats (8)
I believe the answer is:
tenement
'block of flats' is the definition.
(building containing multiple flats)
This is the entire clue.
(Other definitions for tenement that I've seen before include "slum housing?" , "Multiple-occupancy building" , "Permanent property held by tenant" , "Block with several residences" , "Run-down dwelling housing many people" .)