laughter

n. [ AS. hleahtor; akin to OHG. hlahtar, G. gelächter, Icel. hlātr, Dan. latter. See Laugh, v. i. ] 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. [ 1913 Webster ]

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. [ 1913 Webster ]

Archly the maiden smiled, and with eyes overrunning with laughter. Longfellow. [ 1913 Webster ]