epidermis

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. The outer, protective, nonvascular layer of the skin of vertebrates, covering the dermis.
2. n. An integument or outer layer of various invertebrates.
3. n. The outermost layer of cells covering the leaves and young parts of a plant.

Century Dictionary and Cyclopedia

1. n. In anatomy, the cuticle or scarfskin; the non-vascular outer layer of the skin. Its outer portions usually consist of flattened or hardened cells in one or more layers, cohering into a pellicle, which readily peels off and is constantly being shed and renewed. It is derived from the epiblast, and is entered by fine nerve-fibrils, but by no blood-vessels. The following strata are recognized, from without inward: stratum corneum, stratum granulosum, and stratum spinosum. See cuts under skin and sweat-gland.
2. n. In zoology, broadly, some or any outermost integument or tegumentary covering or envelop of the body, or some part of the body: a term nearly synonymous with exoskeleton. Thus, nails, claws, hoofs, horns, scales, feathers, etc., consist of much thickened or otherwise specialized epidermis; the whole skin which a snake sheds is epidermis.
3. n. In embryology, the outermost blastodermic membrane; the ectoderm or epiblast, which will in due course become an epidermis proper.
4. n. In conchology, specifically, the rind or peel covering the shell of a mollusk; the external animal integument of the shell, as distinguished from the shell-substance proper: commonly found as a tough, fibrous, or stringy dark-colored bark, which readily peels off in shreds.
5. n. In botany, the outer layer or layers of cells covering the surfaces of plants.
6. n. Also epiderm.

Wiktionary

1. n. The outer, protective layer of the skin of vertebrates, covering the dermis
2. n. The similar outer layer of cells in invertebrates and plants

GNU Webster's 1913

1. n. (Anat.) The outer, nonsensitive layer of the skin; cuticle; scarfskin. See dermis.
2. n. (Bot.) The outermost layer of the cells, which covers both surfaces of leaves, and also the surface of stems, when they are first formed. As stems grow old this layer is lost, and never replaced.

WordNet 3.0

1. n. the outer layer of the skin covering the exterior body surface of vertebrates