- Anatomy The vertebrate organ of hearing, responsible for maintaining equilibrium as well as sensing sound and divided in mammals into the external ear, the middle ear, and the inner ear. (noun)
- Anatomy The part of this organ that is externally visible. (noun)
- An invertebrate organ analogous to the mammalian ear. (noun)
- The sense of hearing: a sound that grates on the ear. (noun)
- Sensitivity or receptiveness to sound, especially: (noun)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.