Measure jade green boxes (6)
I believe the answer is:
degree
'measure' is the definition.
(degree is a kind of measure)
'jade green boxes' is the wordplay.
'boxes' indicates a hidden word (to box can mean to contain).
'DEGREE' is hidden in the letters of 'jade green'.
(Other definitions for degree that I've seen before include "The measure of a university award?" , "It's given to college graduates" , "Further education award - extent" , "Award conferred by a college or university" , "Fraction of a minute" .)