Part of a cereal plant containing the seeds (3)
I believe the answer is:
ear
'part of a cereal plant containing the seeds' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for ear that I've seen before include "Lend one and listen" , "Organ of hearing" , "Seed-bearing spike" , "Spike (wheat)" , "willingness to listen" .)