noun An animal of the clade (traditionally class) Aves in the phylum Chordata, characterized by being warm-blooded, having feathers and wings usually capable of flight, having a beaked mouth, and laying eggs.
Ducks and sparrows are birds.
noun Any winged animal.
noun A young bird, a nestling.
noun A man, fellow. .mw-parser-output .defdate{font-size:smaller}
noun A girl or woman, especially one considered sexually attractive.