Aves \A"ves\, n. pl. [L., pl. of avis bird.]

(Zo["o]l.) The class of Vertebrata that includes the birds.

Note: Aves, or birds, have a complete double circulation, oviparous, reproduction, front limbs peculiarly modified as wings; and they bear feathers. All existing birds have a horny beak, without teeth; but some Mesozoic fossil birds (Odontornithes) had conical teeth inserted in both jaws. The principal groups are: Carinat[ae], including all existing flying birds; Ratit[ae], including the ostrich and allies, the apteryx, and the extinct moas; Odontornithes, or fossil birds with teeth.

Note: The ordinary birds are classified largely by the structure of the beak and feet, which are in direct relation to their habits. See Beak, Bird, Odontonithes.

Source: Webster's Revised Unabridged Dictionary (1913)