swan song

The Asiatic Society of JapanのBulletin No.8, Oct. 2011に掲載の９月例会の講師を紹介している個所を引用します。
Our speaker was Mr. Jason James, Director of the British Council, and this was his swan song, as he was returning to Britain in just two weeks.
この "swansong" の表現はThe Vote of Thanksの個所にも次ぎの様に出て来ました。
Mr. James had beautifully shown his own skills and qualities as a scholar of both Japanse and music. He was an outstanding, starred first student of Mrs. Yamanouchi's at Cambridge. This lecture had been a wonderful swansong on Mr. James's leaving Japan.
ここでは "swan song" or "swansong" はMr. Jamesが日本を去る前の最後の講演の意味だと分かりますが辞書での説明を見ます。
・Vocabulary.com: a final performance or effort (especially before retirement): This unusual show has been described by Mr. Cattelan as his swan song.
・Wordnik: The fabled song of a dying swan; hence, a last poem or musical work, written just before the composer's death.
スペルは "swansong"/ "swan song" の他に "swan-song" もありましたが、"swan song" で載せている辞書が大半でした。