|1.||the last act, appearance, publication, or utterance of a person before retirement or death|
|2.||the song that a dying swan is said to sing|
A final accomplishment or performance, one's last work. For example, I'm resigning tomorrow; this project was my swan song. This term alludes to the old belief that swans normally are mute but burst into beautiful song moments before they die. Although the idea is much older, the term was first recorded in English only in 1890.