Residential district on a city's outskirts (8)
I believe the answer is:
suburbia
'residential district on a city's outskirts' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for suburbia that I've seen before include "Outer city regions" , "Residential districts on the outskirts of a city" , "Residential district on a city's outskirts" , "Pet Shop Boys song" , "Residential area away from city centre" .)