Source : Webster's Revised Unabridged Dictionary (1913)

Grison \Gri"son\, n. [F., fr. grison gray, gray-haired, gris
   gray. See {Gris}.] (Zo["o]l.)
   (a) A South American animal of the family Mustelidae
       ({Galictis vittata}). It is about two feet long,
       exclusive of the tail. Its under parts are black. Also
       called {South American glutton}.
   (b) A South American monkey ({Lagothrix infumatus}), said to
       be gluttonous.