Swan \Swan\ (sw[o^]n), n. [AS. swan; akin to D. zwaan,
         OHG.
   swan, G. schwan, Icel. svanr, Sw. svan, Dan. svane;
         and
   perhaps to E. sound something audible.]
   1.
         (Zool.) Any one of numerous species of large aquatic birds

              belonging to Cygnus,
         Olor, and allied genera of
         the
      subfamily
         Cygninae. They have a
         large and strong beak
      and a
         long neck, and are noted for their graceful
      movements
         when swimming. Most of the northern species are
     
         white. In literature the swan was fabled to sing a
     
         melodious song, especially at the time of its death.
     
         [1913 Webster]

   Note: The European white, or mute, swan
         (Cygnus gibbus),
         which is most commonly domesticated, bends its neck in
         an S-shaped curve. The whistling, or trumpeting, swans
         of the genus Olor do not
         bend the neck in an S-shaped
         curve, and are noted for their loud and sonorous cry,
         due to complex convolutions of the windpipe. To this
         genus belong the European whooper, or whistling swan
         (Olor cygnus), the
         American whistling swan (Olor Columbianus), and the trumpeter swan
         (Olor
         buccinator). The Australian black swan (Chenopis atrata) is
         dull black with white on the wings, and has
         the bill carmine, crossed with a white band. It is a
         very graceful species and is often domesticated. The
         South American black-necked swan (Sthenelides
         melancorypha) is a very beautiful and graceful
         species, entirely white, except the head and neck,
         which are dark velvety seal-brown. Its bill has a
         double bright rose-colored knob.
         [1913 Webster]

   2. Fig.: An appellation for a sweet
         singer, or a poet noted
      for grace and melody; as
         Shakespeare is called the swan of
      Avon.
      [1913
         Webster]

   3. (Astron.) The constellation Cygnus.
     
         [1913 Webster]

   Swan
         goose (Zool.), a bird of India
         (Cygnopsis
         cygnoides)
      resembling both the swan and
         the goose.

   Swan
         shot, a large size of shot used in
         fowling.
      [1913 Webster]