Source : Webster's Revised Unabridged Dictionary (1913)

Cockatoo \Cock`a*too\, n. [Malayan kakat[=u]a.] (Zo["o]l.)
   A bird of the Parrot family, of the subfamily {Cacatuin[ae]},
   having a short, strong, and much curved beak, and the head
   ornamented with a crest, which can be raised or depressed at
   will. There are several genera and many species; as the
   broad-crested ({Plictolophus, or Cacatua, cristatus}), the
   sulphur-crested ({P. galeritus}), etc. The palm or great
   black cockatoo of Australia is {Microglossus aterrimus}.