laughing \laugh"ing\, a.  n.
   from laugh, v. i.
   1913 webster

   laughing falcon zool., a south american hawk
      herpetotheres cachinnans; -- so called from its notes,
      which resemble a shrill laugh.

   laughing gas chem., nitrous oxide, also called
      hyponitrous oxide, or protoxide of nitrogen; -- so called
      from the exhilaration and laughing which it sometimes
      produces when inhaled. it has been much used as an
      anaesthetic agent, though now its use is primarily in
      dentistry

   laughing goose zool., the european white-fronted goose.
      

   laughing gull. zool.
   a a common european gull xema ridibundus; -- called
       also pewit, black cap, red-legged gull, and sea
       crow.
   b an american gull larus atricilla. in summer the head
       is nearly black, the back slate color, and the five outer
       primaries black.

   laughing hyena zool., the spotted hyena. see hyena.

   laughing jackass zool., the great brown kingfisher
      dacelo gigas, of australia; -- called also giant
      kingfisher, and gogobera.

   laughing owl zool., a peculiar owl sceloglaux
      albifacies of new zealand, said to be on the verge of
      extinction. the name alludes to its notes.
      1913 webster
see also:
laugh laughing falcon herpetotheres cachinnans laughing gas laughing goose laughing gull 
xema ridibundus pewit black cap red-legged gull sea crow 
larus atricilla laughing hyena hyena laughing jackass dacelo gigas 
giant kingfisher gogobera laughing owl sceloglaux albifacies