Ballet dress (4)
I believe the answer is:
tutu
'ballet dress' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for tutu that I've seen before include "Giselle's skirt" , "South African archbishop, b. 1931" , "The old primate" , "very short garment" , "Short skirt for ballet dancer" .)