(n.) 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.

Homeric laughter amusement belly laugh boff boffola burst of laughter cachinnation cackle chortle chortling chuckle convulsion crow fit of laughter frivolity fun gales of laughter giggle glee gleefulness guffaw ha-ha hearty laugh hee-haw hee-hee high glee hilariousness hilarity ho-ho horselaugh jocularity jocundity jolliness jollity joviality joy joyfulness joyousness laugh laughing levity merriment merriness mirth mirthfulness outburst of laughter peal of laughter risibility roar of laughter shout shout of laughter shriek snicker snickering snort tee-hee titter yuck yuk-yuk