Black in heraldry (5)
I believe the answer is:
sable
'black in heraldry' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for sable that I've seen before include "Black (heraldry); fur" , "Marten's fur - dark black" , "North Asian marten" , "Antelope, fur" , "Bales of expensive Russian fur" .)