(swon, swôn) noun
1. A large, web–footed, long–necked bird (subfamily Cygninae), allied to but heavier than the goose, and noted for its grace on the water, as the whooper, the trumpeter swan, and the common North American whistling swan (Cygnus columbiana). The male is a cob, and the female is a pen.
2. Figuratively, a poet or singer. [OE]
TRUMPETER SWAN
(Body length from 4 to 4 1/2 feet)

(swon, swôn) v.i. U.S. Dial.
Swear: chiefly in the phrase I swan, an exclamation of amazement. [Prob. <dial. E (Northern) Is' wan, lit., I shall warrant, used as euphemism for swear]

(swon, swôn)
The constellation Cygnus. See under CONSTELLATION.