Cambridgeshire city (3)
I believe the answer is:
ely
'cambridgeshire city' is the definition.
(Ely is a city in Cambridgeshire)
This is the entire clue.
(Other definitions for ely that I've seen before include "Cambs. city" , "Fenland cathedral town" , "English cathedral city" , "Cathedral city in East Anglia" , "Small city in Cambridgeshire" .)