/ Dictionary / Index T tympanum: Meaning and Definition of Find definitions for: tym•pa•num Pronunciation: (tim'pu-num), [key] — pl. -nums, -na Seemiddle ear. Seetympanic membrane. the recessed, usually triangular space enclosed between the horizontal and sloping cornices of a pediment, often decorated with sculpture. a similar space between an arch and the horizontal head of a door or window below. the diaphragm of a telephone. a drum or similar instrument. the stretched membrane forming a drumhead. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: tympanum (Thesaurus) tympanoplasty tympany Related Content Daily Word Quiz: soporific Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language