Noun | 1. | ![]() bird - warm-blooded egg-laying vertebrates characterized by feathers and forelimbs modified as wings Apodiformes, order Apodiformes - swifts; hummingbirds swift - a small bird that resembles a swallow and is noted for its rapid flight crested swift, tree swift - birds of southeast Asia and East Indies differing from true swifts in having upright crests and nesting in trees hummingbird - tiny American bird having brilliant iridescent plumage and long slender bills; wings are specialized for vibrating flight |