Bride's dress (4)
I believe the answer is:
gown
'bride's dress' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for gown that I've seen before include "Elegant dress" , "Loose flowing garment for woman or judge" , "Woman's long dress or judge's robe" , "Garment (academic, formal, or protective)" , "Long formal dress" .)