Green cotton (4)
I believe the answer is:
lawn
This clue is a double definition.
'green' is the first definition.
(I've seen this before)
'cotton' is the second definition.
(thesaurus)
(Other definitions for lawn that I've seen before include "that may be cut in strips?" , "Grassy patch" , "Cultivated and mowed grass" , "Stretch of grass" , "Grassed area" .)