Source : Webster's Revised Unabridged Dictionary (1913)

Graylag \Gray"lag`\, n. (Zo["o]l.)
   The common wild gray goose ({Anser anser}) of Europe,
   believed to be the wild form of the domestic goose. See
   Illust. of {Goose}.

Source : WordNet®

graylag
     n : common gray wild goose of Europe; ancestor of many domestic
         breeds [syn: {greylag}, {greylag goose}, {Anser anser}]