Middle ear? (3)
I believe the answer is:
cob
'middle ear?' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for cob that I've seen before include "A loaf; a nut; a horse" , "Horse, male swan and loaf of bread" , "mount" , "Hazelnut" , "mixture of clay and straw" .)