King cut short by top officer taps part of ear (7)
I believe the answer is:
cochlea
'part of ear' is the definition.
('cochlea' is part of 'ear')
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for cochlea that I've seen before include "there's a cavity, as we hear" , "Spiral tube in inner ear" , "Coiled tube in the inner ear" , "A cloche (anag) - spiral cavity of the inner ear" , "Spiral tube inside ear" .)