1. The outermost layer of the skin of vertebrates; epidermis.
2. The strip of hardened skin at the base and sides of a fingernail or toenail.
3. Dead or cornified epidermis.
4. Zoology. The noncellular, hardened or membranous protective covering of many invertebrates, such as the transparent membrane that covers annelids.
5. Botany. The layer of cutin covering the epidermis of the aerial parts of plants.

[Latin cutīcula, diminutive of cutis, skin.]

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.