The Collaborative International Dictionary of English v.0.48:

Kraken \Kra"ken\, n. [Prob. from OSw. krake, or ODan. krage the
   trunk of a tree, the branches of which are not entirely cut
   off, to which it was likened by the Norwegian mariners.]
   A fabulous Scandinavian sea monster, often represented as
   resembling an island, but sometimes as resembling an immense
   octopus.
   [1913 Webster]

         To believe all that has been said of the sea serpent or
         kraken, would be credulity; to reject the possibility
         of their existence, would be presumption. --Goldsmith.
   [1913 Webster]

         Like a kraken huge and black.            --Longfellow.
   [1913 Webster]