University replaces faculty's third head (5)
I believe the answer is:
skull
'head' is the definition.
(I've seen this in another clue)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for skull that I've seen before include "Cranium" , "brains here" , "Bony part of head" , "Enclosure for the brain" , "Head bone" .)