Ballerina's hairstyle (3)
I believe the answer is:
bun
'ballerina's hairstyle' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for bun that I've seen before include "Small cake - tied-up hair" , "One from Chelsea" , "Hair in tight coil" , "Small rounded bread or cake" , "Hairstyle, cake" .)