[ 'tɪmpənəm ]
■ noun ( plural ~s or tympana -nə )
1》 Anatomy & Zoology the membrane forming part of the organ of hearing, which vibrates in response to sound waves; the eardrum.
2》 Architecture a vertical recessed triangular space forming the centre of a pediment or over a door.
Origin
C17: via L. from Gk tumpanon 'drum'.