1. (n.) The plain semidome of an apse; sometimes used for the entire apse.

2. (n.) The external ear; esp. the largest and deepest concavity of the external ear, surrounding the entrance to the auditory canal.

Eustachian tube alembic auditory apparatus auditory canal auditory meatus auditory nerve auditory ossicles auditory tube auricle basilar membrane bony labyrinth caldron cauliflower ear cochlea conch concha crucible drumhead ear ear lobe eardrum endolymph engine external ear hammer incus inner ear lathe lobe lobule lug machine malleus mastoid process melting pot middle ear mortar motor organ of Corti outer ear oval window perilymph pinna retort round window secondary eardrum semicircular canals shell stapes stirrup test tube transducer transformer tympanic cavity tympanic membrane tympanum vestibule