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.
Etymology: L f. Gk tumpanon drum f. tupto strike
Useful english dictionary. 2012.