Eardrum - definition of eardrum by The Free Dictionary
ear·drum (îr′drŭm′) n. The thin, semitransparent, oval-shaped membrane that separates the middle ear from the external ear. Also called tympanic membrane, tympanum. eardrum (ˈɪəˌdrʌm) n (Anatomy) the nontechnical name for tympanic membrane ear•drum...