(informal) The spotted hyena (Crocuta crocuta); so called because of the resemblance of its call to human laughter.

(Australia, obsolete) The laughing kookaburra, Dacelo novaeguineae.

Nitrous oxide, especially when used as an anaesthetic.

A common European gull (Xema ridibundus). / An American gull (Leucophaeus atricilla); in summer the head is nearly black, the back slate color, and the five outer primaries black.

An owl (Sceloglaux albifacies) of New Zealand, now probably extinct, named for its cry.

A South American hawk (Herpetotheres cachinnans), so called from its notes, which resemble a shrill laughing.

Dated form of laughing hyena.

A small pigeon (Spilopelia senegalensis) native to the tropics in Africa south of the Sahara; the Middle East; and southern Asia east to India.

Parodying an ostentatious expression of evilness in online written forums such as chat rooms.

A signature laugh associated with villains in films and acting, sometimes represented by muahahaha or bwahaha.