Pronunciation: (tim'pu-num), [key]
—pl. -nums, -naPronunciation: (-nu). [key]
1. Anat., Zool.
a. See middle ear.
b. See tympanic membrane.
a. the recessed, usually triangular space enclosed between the horizontal and sloping cornices of a pediment, often decorated with sculpture.
b. a similar space between an arch and the horizontal head of a door or window below.
3. Elect.the diaphragm of a telephone.
4. a drum or similar instrument.
5. the stretched membrane forming a drumhead.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.