Corn core (3)
I believe the answer is:
cob
'corn core' 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 "mixture of clay and straw" , "Horse, male swan and loaf of bread" , "A loaf; a nut; a horse" , "Swan of Jacobean origin" , "Source of bread" .)