Small jazz band or dance band (5)
I believe the answer is:
combo
I believe this clue is a double definition.
'small jazz band' is the first definition.
(I've seen this before)
'dance band' is the second definition.
(combo is a kind of dance band)
(Other definitions for combo that I've seen before include "Small jazz or dance band" , "Small jazz group" , "Small pop group" , "musicians" , "Small (jazz or rock) band" .)