Horn"bill` (?), n. (Zoöl.) Any bird of the family Bucerotidæ, of which about sixty species are known, belonging to numerous genera. They inhabit the tropical parts of Asia, Africa, and the East Indies, and are remarkable for having a more or less horn-like protuberance, which is usually large and hollow and is situated on the upper side of the beak. The size of the hornbill varies from that of a pigeon to that of a raven, or even larger. They feed chiefly upon fruit, but some species eat dead animals.

• Any of various birds of the family Bucerotidae, with bills resembling a cow's horn. Many species have a casque above the bill, and many imprison their young in a tree.