Gold and black ball (3)
I believe the answer is:
orb
'ball' is the definition.
('orb' can be a synonym of 'ball')
'gold and black' is the wordplay.
'gold' becomes 'or' ('or' is the heraldic name for gold).
'and' means one lot of letters go next to another.
'black' becomes 'b' (as in pencil classifications).
'or'+'b'='ORB'
(Other definitions for orb that I've seen before include "Sovereign artefact" , "Ornamental sphere" , "A poetic eye, bro" , "The World" , "Part of royal regalia" .)