Cerebellum part (4)
I believe the answer is:
lobe
'cerebellum part' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for lobe that I've seen before include "could be site of a 24 [STUD]" , "Appendage to ear" , "Division of the lungs or brain" , "Rounded part (of organ)" , "Leaf division" .)