"The Big Apple" (3,4)
I believe the answer is:
new york
'the big apple' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for new york that I've seen before include "Chrysler Building city" , "Worn key (anag.)" , "repeatedly mentioned in song" , "Great city called the Big Apple" , "US state, one of the original 13" .)