Box of various parts (4)
I believe the answer is:
spar
'box' is the definition.
(spar can mean to box)
'of various parts' is the wordplay.
'of' indicates the answer is hidden within the clue.
'SPAR' is hidden within 'various parts'.
(Other definitions for spar that I've seen before include "Mineral; strong pole" , "Translucent mineral" , "Scrap" , "dispute" , "Wooden pole -- box" .)