Source : Webster's Revised Unabridged Dictionary (1913)

Grizzly \Griz"zly\, a.
   Somewhat gray; grizzled.

         Old squirrels that turn grizzly.         --Bacon.

   {Grizzly bear} (Zo["o]l.), a large and ferocious bear ({Ursus
      horribilis}) of Western North America and the Rocky
      Mountains. It is remarkable for the great length of its
      claws.

Source : WordNet®

Ursus horribilis
     n : powerful brownish-yellow bear of the uplands of western
         North America [syn: {grizzly}, {grizzly bear}, {silvertip},
          {silver-tip}, {Ursus arctos horribilis}]