a bird of the parrot family, of the subfamily cacatuinae, 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, / cacatua, cristatus), the sulphur-crested (p. galeritus), etc. the palm or great black cockatoo of australia is microglossus aterrimus.