Order about a month before a dance (5,4)
I believe the answer is:
bossa nova
'dance' is the definition.
(Brazilian dance)
'order about a month before a' is the wordplay.
'order about' becomes 'boss' (I've seen this in another clue).
'month' becomes 'Nov' (abbreviation for November).
'before' says to put letters next to each other.
'boss'+'a'+'nov'+'a'='BOSSA NOVA'
(Other definitions for bossa nova that I've seen before include "lively dance" , "steps taken" , "Brazil's measure" , "(Music for) a Brazilian dance" , "Brazilian music, rhythmically related to the samba" .)