Bird  n. 1 two-legged feathered winged vertebrate, egg-laying and usu. Able to fly. 2 slang young woman. 3 slang person. 4 slang prison; prison sentence.  a bird in the hand something secured or certain. The birds and the bees euphem. Sexual activity and reproduction. Birds of a feather similar people. For the birds colloq. Trivial, uninteresting. Get the bird slang be rejected, esp. By an audience. [old english]