Source : Webster's Revised Unabridged Dictionary (1913)

Pluto \Plu"to\, n. [L., fr. Gr. ?.] (Class. Myth.)
   The son of Saturn and Rhea, brother of Jupiter and Neptune;
   the dark and gloomy god of the Lower World.

   {Pluto monkey} (Zo["o]l.), a long-tailed African monkey
      ({Cercopithecus pluto}), having side whiskers. The general
      color is black, more or less grizzled; the frontal band is
      white.

Source : WordNet®

Pluto
     n 1: a cartoon character created by Walt Disney
     2: (Greek mythology) the god of the underworld in ancient
        mythology; brother of Zeus and husband of Persephone [syn:
         {Hades}, {Aides}, {Aidoneus}]
     3: the second smallest planet and the farthest known from the
        sun; has the most elliptical orbit of all the planets