Chamber group (5)
'chamber group' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for octet that I've seen before include "Piece for eight players" , "Set of eight" , "What takes members up to eighth" , "music group" , "Group that plays" .)
'chamber group' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for trio that I've seen before include "Group of three (musicians)" , "Beethoven's 'Archduke': famous piece written for this ensemble" , "Ensemble musical piece, eg Beethoven's 'Archduke'" , "Three of a kind" , "Riot (anag)" .)