The Collaborative International Dictionary of English v.0.48:
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.
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.
2. Fig.: An appellation for a sweet singer, or a poet noted
for grace and melody; as Shakespeare is called the swan of
3. (Astron.) The constellation Cygnus.
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.