Remark to audience (5)
I believe the answer is:
aside
'remark to audience' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for aside that I've seen before include "Line spoken to theatre audience" , "Out of other people's hearing" , "kept in reserve" , "Digression" , "Remark by an actor, directly to audience say" .)