A paint mixed to give a glossy surface (6)
I believe the answer is:
patina
'a glossy surface' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Perhaps you can see an association between them that I don't see?
'a paint mixed' is the wordplay.
'mixed' is an anagram indicator.
'a'+'paint'='apaint'
'apaint' is an anagram of 'PATINA'.
'to give' is the link.
Can you help me to learn more?
(Other definitions for patina that I've seen before include "thin coating" , "Film forming on bronze" , "Fine coating on surface" , "Brownish surface film on old bronze" , "Gloss or colour produced by a paint" .)