Return copies include one in colour (5)
I believe the answer is:
sepia
'colour' is the definition.
(I know that sepia is a type of brown)
'return copies include one' is the wordplay.
'return' says the letters should be written backwards.
'copies' becomes 'apes' ('ape' can be a synonym of 'copy').
'include' indicates putting letters inside.
'one' becomes 'I' (Roman numeral).
'apes' placed around 'i' is 'aipes'.
'aipes' back-to-front is 'SEPIA'.
'in' acts as a link.
(Other definitions for sepia that I've seen before include "Brown of old photos" , "tone of pictures?" , "Pigment obtained from cuttlefish ink" , "Colourant" , "Colour of old photographs" .)