n. (pl. tympanums or tympana) 1 Anat. a the middle ear. b the tympanic membrane. 2 Zool. the membrane covering the hearing organ on the leg of an insect. 3 Archit. a a vertical triangular space forming the centre of a pediment. b a similar space over a door between the lintel and the arch; a carving on this space. 4 a drum-wheel etc. for raising water from a stream.
[ L f. Gk tumpanon drum f. tupto strike ]