ear-drum (n.)

"organ of hearing," Old English eare "ear," from Proto-Germanic *auzon (source also of Old Norse eyra, Danish øre, Old Frisian are, Old Saxon ore, Middle Dutch ore, Dutch oor, Old High German ora, German Ohr, Gothic auso), from PIE *ous- "ear" (source also of Greek aus, Latin auris, Lithuanian ausis, Old Church Slavonic ucho, Old Irish au "ear," Avestan usi "the two ears").

þe harde harte of man, þat lat in godis word atte ton ere & vt atte toþir. [sermon, c. 1250]

In music, "capability to learn and reproduce by hearing," 1520s, hence play by ear (1670s). The belief that itching or burning ears means someone is talking about you is mentioned in Pliny's "Natural History" (77 C.E.). Until at least the 1880s, even some medical men still believed piercing the ear lobes improved one's eyesight. Meaning "handle of a pitcher" is mid-15c. (but compare Old English earde "having a handle"). To be wet behind the ears "naive" is from 1902, American English. Phrase walls have ears is attested from 1610s. French orielle, Spanish oreja are from Latin auricula (Medieval Latin oricula), diminutive of auris.

early 15c., drom, "percussive musical instrument consisting of a hollow wooden or metallic body and a tightly stretched head of membrane," probably from Middle Dutch tromme "drum," a common Germanic word (compare German Trommel, Danish tromme, Swedish trumma) and probably imitative of the sound of one.

Not common before 1570s; the slightly older, and more common at first, word was drumslade, apparently from Dutch or Low German trommelslag "drum-beat," "though it does not appear how this name of the action came to be applied to the instrument" [OED], and the English word might be a shortening of this. Other earlier words for it were tabour (c. 1300, ultimately from Persian; see tabor) and timpan (Old English; see tympanum).

In machinery, the word was applied to various contrivances resembling a drum from 1740. In anatomy, "the tympanum of the ear," 1610s. Meaning "receptacle having the form of a drum" is by 1812. Drum-major (1590s) originally was "chief or first drummer of a military regiment;" later "one who directs the evolutions of a marching corps."