Different article in gold (5)
I believe the answer is:
other
'different' is the definition.
(I've seen this before)
'article in gold' is the wordplay.
'article' becomes 'the' (the 'definite article' part of speech).
'in' is an insertion indicator.
'gold' becomes 'or' ('or' is the heraldic name for gold).
'the' placed within 'or' is 'OTHER'.
(Other definitions for other that I've seen before include "Alternative - unrelated" , "Different (from those mentioned)" , "One may be significant" , "Throe (anag)" , "Different, disparate" .)