The cavity of the middle ear, which is separated from the outer ear by the eardrum.

cf. Tympanal organ - the hearing system of insects.

ear drum (pop)

Triangular space in the pediment of a classical building, semicircular solid space between the arch and lintel of a Gothic doorway or between the covering arch and lights of a window.    (Wood, Ma [..]

(n) the main cavity of the ear; between the eardrum and the inner ear(n) the membrane in the ear that vibrates to sound(n) a large hemispherical brass or copper percussion instrument with a drumhead t [..]

See hearing mechanism.

(Lat. "drum") In classical architecture, the triangular area enclosed by a pediment, often decorated with sculptures. In medieval architecture, the semi-circular area over a a door's li [..]

The external eardrum.

The auditory membrane or ear-drum of various insects. Type.

 auditory membrane in certain insects.  

Vertical triangular space, plain or with relief decoration, between the slopes of a roof and the horizontal cornice of a temple or other building with a pediment.

(architecture) A triangular space between the sides of a pediment. (architecture) The space within an arch, and above a lintel or a subordinate arch, spanning the opening below the arch. The mid [..]

"drum of the ear," 1610s, from Medieval Latin tympanum, introduced in this sense by Italian anatomist Gabriello Fallopio (1523-1562), from Latin tympanum "a drum, timbrel, tambourine,&q [..]

Eardrum, visible externally on many lizards.