Sausage in a bun (3,3)
I believe the answer is:
hot dog
'sausage in a bun' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for hot dog that I've seen before include "Long roll containing sausage" , "grub?" , "'Frankfurter in a bun (3,3)'" , "Frankfurter in a roll" , "Sausage sandwich - acrobatic skier" .)