Source : Webster's Revised Unabridged Dictionary (1913)

Gnu \Gnu\, n. [Hottentot gnu, or nju: cf. F. gnou.] (Zo["o]l.)
   One of two species of large South African antelopes of the
   genus {Catoblephas}, having a mane and bushy tail, and curved
   horns in both sexes. [Written also {gnoo}.]

   Note: The common gnu or wildebeest ({Catoblephas gnu}) is
         plain brown; the brindled gnu or blue wildebeest ({C.
         gorgon}) is larger, with transverse stripes of black on
         the neck and shoulders.