From Middle English laughter, laghter, laȝter, from Old English hleahtor, from Proto-Germanic *hlahtraz, from Proto-Indo-European *klek-, *kleg- ("to shout").

• (RP) IPA: /ˈlɑːftə/
• (America) enPR: lăfʹtər, IPA: /ˈlæftɚ/

laughter (uncountable)

1. The sound of laughing, produced by air so expelled; any similar sound.

   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.
   • 1646, Thomas Browne, Pseudodoxia Epidemica: […], London: […] T[homas] H[arper] for Edward Dod, […], →OCLC ↗:

     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.

   • 1858 October 15, Henry Wadsworth Longfellow, “The Courtship of Miles Standish”, in The Courtship of Miles Standish, and Other Poems, Boston, Mass.: Ticknor and Fields, →OCLC ↗:

     Archly the maiden smiled, and with eyes overrunning with laughter.

3. (archaic) A reason for merriment.

• laugh

• French: rire
• German: Gelächter, Lachen
• Italian: risata, riso
• Portuguese: risada, risos
• Russian: смех
• Spanish: risa

• French: rire
• German: Gelächter, Lachen
• Italian: risata
• Portuguese: risada, riso
• Russian: смех

1. Surname.