tympanum n.

late 15c., "symbol, emblem," from Latin typus "figure, image, form, kind," from Greek typos "a blow, dent, impression, mark, effect of a blow; figure in relief, image, statue; anything wrought of metal or stone; general form, character; outline, sketch," from root of typtein "to strike, beat," from PIE *tup-, variant of root *(s)teu- (1) "to push, stick, knock, beat" (see steep (adj.)).

Extended 1713 to printing blocks of metal or wood with letters or characters carved on their faces, usually in relief, adapted for use in letterpress printing. The meaning "general form or character of some kind, class" is attested in English by 1843, though the corresponding words had that sense in Latin and Greek. To be (someone's) type "be the sort of person that person is attracted to" is recorded from 1934.

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."