Residential district on the outskirts of a city (6)
I believe the answer is:
suburb
'residential district on the outskirts of a city' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for suburb that I've seen before include "Present (bill); melt down (fat)" , "Residential district on a city's outskirts" , "Area on the outskirts of a city" , "Residential district away from city centre" , "Residential city area" .)