Material from the Big Apple plus western half of London (5)
I believe the answer is:
nylon
'material' is the definition.
(I know that nylon is a type of material)
'the big apple plus western half of london' is the wordplay.
'the big apple' becomes 'ny' (short for New York).
'plus' means one lot of letters go next to another.
'western half of' suggests halving the letters (the western or left-hand half).
'london' halved is 'lon'.
'ny'+'lon'='NYLON'
'from' is the link.
(Other definitions for nylon that I've seen before include "Fibrous material" , "Stocking; polymer" , "Hose" , "Artificial fabric" , "Artificial material" .)