Hearing organ (3)
I believe the answer is:
ear
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">hearing organ</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for ear that I've seen before include "Bit of corn" , "Go astray" , "Sense organ" , "Musical ability" , "Lug (colloq.)" .)