noun the constellation cygnus.
2. swan ·noun fig.: an appellation for a sweet singer, or a poet noted for grace and melody; as shakespeare is called the swan of avon.
3. swan ·noun 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.