Hearsay about bit of corn (3)
I believe the answer is:
ear
'bit of corn' is the definition.
('ear' is part of 'corn')
'hearsay about' is the wordplay.
'about' indicates the answer is hidden within the clue (the clue goes around or about the answer).
'EAR' can be found hidden inside 'hearsay'.
(Other definitions for ear that I've seen before include "Organ of hearing" , "See 8" , "Sense organ" , "Go astray" , "organ with drum" .)