Hall sweeper gathers everything (8)
I believe the answer is:
ballroom
'hall' is the definition.
(I've seen this before)
'sweeper gathers everything' is the wordplay.
'sweeper' becomes 'broom' (a broom sweeps things up).
'gathers' indicates putting letters inside.
'everything' becomes 'all' (all things).
'broom' enclosing 'all' is 'BALLROOM'.
(Other definitions for ballroom that I've seen before include "place associated with steps?" , "Place for dance" , "In which the tango or the foxtrot are danced" , "Place for old-fashioned dancing - and romance?" , "Hall for dancing" .)