laughter

noun3

1. •
   the sounds people make when they find something funny

   • Their loud laughter betrayed their presence.
2. •
   A movement (usually involuntary) of the muscles of the laughing face, particularly of the lips, and of the whole body, 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.

   • The act of laughter, which is caused by 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. — 1646
3. •
   (no longer used) A reason for merriment.