bird

Concise Oxford English Dictionary © 2008 Oxford University Press:
bird/bɜːd/

▶noun

• 1 a warm-blooded egg-laying vertebrate animal of a class distinguished by the possession of feathers, wings, and a beak, typically able to fly. [Class Aves.]

• 2 informal a person of a specified kind: she's a sharp old bird.

• 3 Brit. informal a young woman or girlfriend.

– phrases
the bird has flown the person one is looking for has escaped or left.
the birds and the bees informal basic facts about sex and reproduction, as told to a child.
do (one's) bird Brit. informal serve a prison sentence. [bird from rhyming sl. birdlime ‘time’.]
flip someone the bird N. Amer. informal stick one's middle finger up at someone as a sign of contempt or anger.
(strictly) for the birds informal not worthy of consideration.
give someone the bird Brit. informal boo or jeer at someone.
have a bird N. Amer. informal be shocked or agitated.

– derivatives
birdlike adjective.

– origin OE brid ‘chick, fledgling’, of unknown origin.