What does epidermis mean?
The epidermis is the outermost layer of tissue covering the body of an animal or plant. In humans it forms the thin, visible surface of the skin, sitting above the thicker dermis and serving as the body's first barrier against water loss, pathogens, and ultraviolet radiation. Its cells are continually shed and replaced from below, so the entire layer regenerates over a period of weeks. In plants, the epidermis is the single layer of cells coating leaves, stems, and roots, often producing waxy or hairy surfaces that protect against drying out and injury. Because the word is precise and scientific, it appears chiefly in medical, biological, and cosmetic writing rather than casual conversation, where 'skin' does the job. Knowing the term lets readers follow discussions of sunburn, skincare, wounds, and plant structure with confidence.
nounThe outermost layer of cells covering the surface of an animal's or plant's body, in humans forming the thin outer layer of the skin above the dermis.
- The outermost protective layer of cells covering the body of an animal, especially the outer layer of human skin lying above the dermis.
- In botany, the single layer of cells covering the leaves, stems, roots, and other organs of a plant.
"Sunlight damages the epidermis long before it affects the deeper layers of skin."
"The tattoo needle deposits ink beneath the epidermis into the deeper dermis."
"A waxy cuticle on the leaf's epidermis helps the plant conserve water."
Rarely used; epidermis is normally treated as uncountable when discussing the layer generally, and the plural appears only in specialist contexts comparing multiple organisms' tissues.
"The researchers compared the epidermises of several desert plants."
Your epidermis replaces itself entirely roughly every 27 days — you are literally wearing a new skin every month.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of epidermis
The word epidermis entered English in the early 17th century, borrowed via New Latin from Greek. It combines the Greek prefix epi-, meaning 'upon' or 'over', with derma, meaning 'skin', so it literally means 'over-skin'. The same Greek root derma underlies related anatomical terms such as dermis, hypodermis, dermatitis, and dermatology.
Related word forms
How epidermis is actually used
Epidermis is a technical term used mainly in anatomy, dermatology, and botany; in everyday speech people simply say 'skin'. It is formal to scientific in register. The plural 'epidermises' exists but is rare; the word is usually treated as uncountable when referring to the layer generally.
Easily confused with epidermis
The epidermis is the thin, outermost layer of skin, while the dermis is the thicker layer beneath it containing nerves, hair follicles, and blood vessels.