Hammer and anvil site (3)
I believe the answer is:
ear
'hammer and anvil site' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for ear that I've seen before include "Listening organ" , "Organ inside heart" , "Seed-bearing part of wheat" , "Aural appendage" , "Lend one and listen" .)