The Collaborative International Dictionary of English v.0.48:

Grizzly \Griz"zly\, a.
   Somewhat gray; grizzled.
   [1913 Webster]

         Old squirrels that turn grizzly.         --Bacon.
   [1913 Webster]

   Grizzly bear (Zool.), 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.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Grizzly \Griz"zly\, n.; pl. Grizzlies.
   1. (Zool.) A grizzly bear. See under Grizzly, a.
      [1913 Webster]

   2. pl. In hydraulic mining, gratings used to catch and throw
      out large stones from the sluices. [Local, U. S.]
      --Raymond.
      [1913 Webster]

WordNet (r) 3.0 (2006):

grizzly
    adj 1: showing characteristics of age, especially having grey or
           white hair; "whose beard with age is hoar"-Coleridge;
           "nodded his hoary head" [syn: grey, gray, grey-
           haired, gray-haired, grey-headed, gray-headed,
           grizzly, hoar, hoary, white-haired]
    n 1: powerful brownish-yellow bear of the uplands of western
         North America [syn: grizzly, grizzly bear, silvertip,
         silver-tip, Ursus horribilis, Ursus arctos
         horribilis]