horselaugh

from WordNet (r) 3.0 (2006)

horselaugh
    n 1: a loud laugh that sounds like a horse neighing [syn: {hee-
         haw}, {horselaugh}, {ha-ha}, {haw-haw}]

from The Collaborative International Dictionary of English v.0.48

Horselaugh \Horse"laugh`\, n.
   A loud, boisterous laugh; a guffaw. --Pope.
   [1913 Webster]

from Moby Thesaurus II by Grady Ward, 1.0

38 Moby Thesaurus words for "horselaugh":
      Homeric laughter, belly laugh, boff, boffola, burst of laughter,
      cachinnation, cackle, chortle, chuckle, convulsion, crow,
      fit of laughter, gales of laughter, giggle, guffaw, ha-ha,
      hearty laugh, hee-haw, hee-hee, hilarity, ho-ho, laugh, laughing,
      laughter, outburst of laughter, peal of laughter, risibility,
      roar of laughter, shout, shout of laughter, shriek, snicker,
      snigger, snort, tee-hee, titter, yuck, yuk-yuk