Package of paper (4)
I believe the answer is:
ream
'package of paper' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for ream that I've seen before include "Quantity of paper, about 500 sheets" , "Widen out (bore)" , "Lots of paper" , "480 sheets of paper" , "Many sheets - enlarge hole" .)