Tympanic membrane (7)
I believe the answer is:
eardrum
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">tympanic membrane</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for eardrum that I've seen before include "Rude ram (anag.)" , "Ear membrane" , "Vibrating membrane in the head" , "Auditory membrane" , "Aural membrane" .)