(Science: ornithology, zoology) The class of vertebrata that includes the birds.
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: Carinatae, including all existing flying birds; ratitae, including the ostrich and allies, the apteryx, and the extinct moas; odontornithes, or fossil birds with teeth.
The ordinary birds are classified largely by the structure of the beak and feet, which are in direct relating to their habits. See beak, bird, Odontonithes.
Origin: L, pl. Of avis bird.