tympanum
Pronunciation: /ˈtɪmpənəm/
noun ( plural tympanums or tympana /-nə/)
- 1 Anatomy & Zoology the tympanic membrane or eardrum.
- Entomology a membrane covering the hearing organ on the leg or body of some insects, sometimes adapted (as in cicadas) for producing sound.

Origin:
early 17th century: via Latin from Greek tumpanon 'drum', based on tuptein 'to strike'