Bundle of paper (5)
(Other definitions for sheaf that I've seen before include "Bundle, of grain stalks say" , "Reaper's bundle" , "Bundle, as of reeds for thatching" , "Bundle of wheat" , "Bundle of cereal plants" .)
(Other definitions for ream that I've seen before include "Widen out (bore)" , "Make hole larger - lot of paper" , "Quantity of paper, about 500 sheets" , "Twenty quires of paper" , "Many bits of paper" .)