The Collaborative International Dictionary of English v.0.48:

Gull \Gull\, n. [Of Celtic origin; cf. Corn. gullan, W. gwylan.]
   (Zool.)
   One of many species of long-winged sea birds of the genus
   Larus and allied genera.
   [1913 Webster]

   Note: Among the best known American species are the herring
         gull (Larus argentatus), the great black-backed gull
         (L. murinus) the laughing gull (L. atricilla), and
         Bonaparte's gull (L. Philadelphia). The common
         European gull is Larus canus.
         [1913 Webster]

   Gull teaser (Zool.), the jager; -- also applied to certain
      species of terns.
      [1913 Webster]