Dictionary definition · flap
noun
- any broad thin and limber covering attached at one edge; hangs loose or projects freely"he wrote on the flap of the envelope"
- an excited state of agitation"he was in a dither"
- the motion made by flapping up and down
- a movable piece of tissue partly connected to the body
- a movable airfoil that is part of an aircraft wing; used to increase lift or drag
verb
- move in a wavy pattern or with a rising and falling motion"The curtains undulated"
- to flutter noisily when moved by the wind"flags flapped in the strong wind"
- move with a thrashing motion"The bird flapped its wings"
- move with a flapping motion"The bird's wings were flapping"
- make a fuss; be agitated
- pronounce with a flap, of alveolar sounds
Source: Open English WordNet (CC BY 4.0).