Hearing part? (3)
I believe the answer is:
ear
I believe this clue is a double definition.
'hearing' is the first definition.
(ear is a kind of hearing)
'part?' is the second definition.
(ear is a kind of part)
(Other definitions for ear that I've seen before include "one hears" , "Aural appendage" , "willingness to listen" , "Auricle" , "Head of grain" .)