Grison \Gri"son\, n. [F., fr. grison gray, gray-haired, gris gray. See {Gris}.] (Zool.) (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. [1913 Webster]