D defs.my
Entry 1 sense Webster, 1913

Laughter

/lăfʹtər/ · Laugh·ter · IPA /ˈlæftɚ/
01 n. A movement (usually involuntary) of the muscles of the face, particularly of the lips, with a peculiar expression of the eyes, indicating m…
  1. 1.
    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. See: Laugh
    “The act of laughter, which is a sweet contraction of the muscles of the face, and a pleasant agitation of the vocal organs, is not merely, or totally within the jurisdiction of ourselves.” Sir T. Browne.
    “Archly the maiden smiled, and with eyes overrunning with laughter.” Longfellow.