Grain bundle (5)
I believe the answer is:
sheaf
'grain bundle' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for sheaf that I've seen before include "Bundle of wheat" , "Bundle as of arrows or corn stalks" , "Reaper's bundle" , "Bundle of several things tied together" , "Bundle, as of reeds for thatching" .)