Part, portion (5)
I believe the answer is:
piece
I believe this clue is a double definition.
'part' is the first definition.
(I know that part can be written as piece)
'portion' is the second definition.
(I know that piece is a type of portion)
(Other definitions for piece that I've seen before include "Component; portion" , "Part - portion" , "king or queen?" , "man on board" , "that may follow show after work party?" .)