Box with a pole (4)
I believe the answer is:
spar
I believe this is a double definition.
'box' is the first definition.
(spar can mean to box)
'pole' is the second definition.
(I know that spar is a type of pole)
'with a' acts as a link.
(Other definitions for spar that I've seen before include "Mineral; plane's wing beam" , "Fight (in training) - pole (on boat)" , "dispute" , "Raps with wooden beam" , "Stout pole to support rigging" .)