The word swan is derived from Old English swan, akin to the German Schwan and Dutch zwaan and Swedish svan, in turn derived from Indo-European root *swen (to sound, to sing).
Young swans are known as swanlings or as cygnets, from Greek κύκνος, kýknos and from the Latin word cygnus ("swan") and the Old French suffix -et ("little").
An adult male is a cob, from Middle English cobbe (leader of a group); an adult female is a pen.