Portion; component (5)
I believe the answer is:
piece
This clue is a double definition.
'portion' is the first definition.
(I know that piece is a type of portion)
'component' is the second definition.
(I've seen this in another clue)
(Other definitions for piece that I've seen before include "Section; firearm" , "that may follow show after work party?" , "Musical work; bit" , "A bit of something" , "Musical composition" .)