noun (n)

• the sound of laughing(noun.communication)

  Synonym:
  laugh
  

  source: wordnet30
• the activity of laughing; the manifestation of joy or mirth or scorn(noun.act)

  Example:
  He enjoyed the laughter of the crowd.
  

  source: wordnet30
• A movement (usually involuntary) of the muscles of the face, particularly of the lips, with a peculiar expression of the eyes, indicating merriment, satisfaction, or derision, and usually attended by a sonorous and interrupted expulsion of air from the lungs. See Laugh, v. i.(noun)

  source: webster1913