Clique, set (5)
I believe the answer is:
group
I believe this is a double definition.
'clique' is the first definition.
(I've seen this in another clue)
'set' is the second definition.
(I know that group is a type of set)
(Other definitions for group that I've seen before include "Clique" , "Number or people or things classed together" , "Unit of pop performers" , "Aggregation" , "Band, assembly" .)