What does corium mean?
Corium is the anatomical name for the thick inner layer of the skin, lying directly beneath the epidermis and more commonly known as the dermis or true skin. It houses the structures that keep skin alive and functional: blood vessels, nerve endings, sweat glands, hair follicles, and an elastic meshwork of collagen fibres that gives skin its strength and resilience. Because its cells are not continuously shed, ink injected into the corium makes tattoos permanent, while damage to this layer — as in deep burns — can leave lasting scars. The word also has a second life in the leather trade, where the corium of an animal hide is precisely the portion transformed into genuine leather. Derived from the Latin word for skin or hide, corium remains chiefly a technical term in anatomy, dermatology, and tanning, prized for its precision rather than everyday use.
nounThe dense inner layer of the skin beneath the epidermis, containing blood vessels, nerve endings, hair follicles, and sweat glands; also called the dermis. In the leather trade, it refers to the layer of a hide from which true leather is made.
- The inner, vascular layer of the skin lying beneath the epidermis; the dermis or true skin.
- In tanning and leather-making, the layer of a hide or skin from which genuine leather is produced.
"Under the microscope, the corium revealed a dense weave of collagen fibres interlaced with tiny blood vessels."
"The tattoo needle deposits ink into the corium, where it remains permanently because that layer's cells are never shed."
"Full-grain leather retains the entire surface of the original corium, making it the most durable grade of hide."
The learned Latinate plural "coria" is standard in anatomical writing; "coriums" is rare.
"Histologists compared the thickness of the coria across several mammalian species."
Every leather belt you own is made almost entirely of corium — the same layer of your own skin that blisters when you burn yourself.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of corium
Corium comes directly from Latin corium, meaning "skin" or "hide," which ultimately traces back to the Proto-Indo-European root *(s)ker-, associated with cutting or separating hides. The same ancient root gave English words such as cortex, scurf, and shear. The term entered scientific English as an anatomical label for the true skin, and its derivative coriaceous — "leathery" — preserves its connection to the tanning trade.
How corium is actually used
Corium is primarily a technical term used in anatomy, histology, dermatology, and the leather industry; in everyday medical contexts, "dermis" is far more common. The plural is "coria."
Easily confused with corium
Curium is a synthetic radioactive chemical element (Cm, atomic number 96), whereas corium is the inner layer of the skin.
The epidermis is the thin outermost protective layer of the skin, while the corium (dermis) is the thicker living layer beneath it.