Cornea, from the Latin, cornu, animal horn, and corneus, horny (i.e., tough and hard like a horn).

It seems strange for the cornea, the transparent and seemingly delicate anterior surface of the eye, to be etymologically related to an animal horn but it was recognized long ago that the structure, when dissected, is surprisingly hard; thus its "horny" nature.

The stratum corneum, the name given to tough outer layer of the skin, also comes from cornu, as does the corniculate cartilage of the larynx (literally, corniculate means "shaped like a little horn").

Some other words derived from cornu include Capricorn (literally, a goat's horn), cornucopia (the horn of plenty), and cornet (which, like all musical horns, can trace its ultimate ancestry back to the animal horns used as musical instruments by prehistoric humans).

Note that although the coronoid processes of the mandible and ulna have a shape reminiscent of animals horns, "coronoid" is derived not from cornu but from korone, Latin for crow, or korax, Latin for raven. Charitably, these structures also resemble a corvid's beak, though the Greeks often used korax for many structures with a slightly hooked or pointed tip, such as the handles of their doors (see coracoid).