Hearing about organ (3)
I believe the answer is:
ear
'organ' is the definition.
(the ear is an organ)
'hearing about' is the wordplay.
'about' indicates a hidden word (the clue goes around or about the answer).
'EAR' can be found hidden inside 'hearing'.
(Other definitions for ear that I've seen before include "Shell-like; corn" , "Lend one and listen" , "cut" , "Seed-bearing part of corn" , "Aural organ" .)