What is the meaning of flap?

noun

• Any broad thin and limber covering attached at one edge; hangs loose or projects freely.
  • usage: "he wrote on the flap of the envelope"
• An excited state of agitation.
  • usage: "he was in a dither"; "there was a terrible flap about the theft"
  • synonyms: dither, pother, fuss, tizzy
• The motion made by flapping up and down.
  • synonyms: flapping, flutter, fluttering
• 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.
  • synonyms: flaps

verb

• Move in a wavy pattern or with a rising and falling motion.
  • usage: "The curtains undulated"; "the waves rolled towards the beach"
  • synonyms: roll, undulate, wave
• Move noisily.
  • usage: "flags flapped in the strong wind"
• Move with a thrashing motion.
  • usage: "The bird flapped its wings"; "The eagle beat its wings and soared high into the sky"
  • synonyms: beat
• Move with a flapping motion.
  • usage: "The bird's wings were flapping"
  • synonyms: beat
• Make a fuss; be agitated.
  • synonyms: dither, pother
• Pronounce with a flap, of alveolar sounds. .