Heraldic term for silver (6)
I believe the answer is:
argent
'heraldic term for silver' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for argent that I've seen before include "Silver on a coat of arms" , "Heraldic term for silver" , "(In heraldry) silver - garnet (anag)" , "Colour" , "Tincture of silver in heraldry" .)