ETYM Old Eng. flappe, flap, blow, bly-flap; cf. Dutch flap, and Eng. flap.
1. Any broad thin and limber covering attached at one edge; hangs loose or projects freely.
2. A movable piece of tissue partly connected to the body.
3. A movable airfoil that is part of an aircraft wing; used to increase lift or drag; SYN. flaps.
4. The motion made by flapping up and down; SYN. flapping, flopping, flutter, fluttering.

1. To move up and down rapidly, in the fashion of wings.
2. To move noisily.
3. To pronounce with a flap, of alveolar sounds.