PIE*gher、丸い、円、語源的にはyardと同じ、歌手やダンサーの輪、後にコーラス。
When a Poet wished to bring out a piece, he asked a Chorus from the Archon, and the expenses, being great, were defrayed by some rich citizen (the khoregos): it was furnished by the Tribe and trained originally by the Poet himself" [Liddell & Scott]Originally in English used in theatrical sense; meaning of "a choir" first attested 1650s. Meaning "the refrain of a song" (which the audience joins in singing) is 1590s. As a verb, 1703, from the noun. Chorus girl is 1894.