Words related to *gher-
c. 1300, "joyful song," also a kind of dance in a ring, from Old French carole "kind of dance in a ring, round dance accompanied by singers," a word of uncertain origin. Perhaps from Medieval Latin choraula "a dance to the flute," from Latin choraules "flute-player," from Greek khoraulēs "flute player who accompanies the choral dance," from khoros "chorus" (see chorus) + aulein "to play the flute," from aulos "reed instrument" (see alveolus). OED writes that "a Celtic origin is out of the question." The meaning "Christmas hymn of joy" is attested from c. 1500.
c. 1300, queor "part of the church where the choir sings," from Old French cuer, quer "(architectural) choir of a church; chorus of singers" (13c., Modern French choeur), from Latin chorus "choir" (see chorus). Meaning "band of singers" in English is from c. 1400, quyre. Re-spelled mid-17c. in an attempt to match classical forms, but the pronunciation has not changed.
1828, "sacred choral song; musical composition in harmony, suited for performance by a choir," from German Choral "metrical hymn in Reformed church," shortened from Choralgesang "choral song," translating Medieval Latin cantus choralis, from Latin choralis "belonging to a chorus or choir," from chorus (see chorus). The -e was added to indicate stress. Meaning "group of singers performing choral music" is from 1942.
1560s, in drama, "person who speaks the prologue and explains or comments on events on stage," from Latin chorus "a dance in a circle, the persons singing and dancing, the chorus of a tragedy," from Greek khoros "round dance; dancing-place; band of dancers; company of persons in a play, under a leader, who take part in dialogue with the actors and sing their sentiments at intervals."
The Greek word is of uncertain origin, because the original sense is unknown. Perhaps it is from PIE root *gher- (1) "to grasp, enclose," if the original sense of the Greek word is "enclosed dancing floor," or *gher- (2) "to like, want," if the original notion is "to rejoice."
Extension from dance to voice is because Attic drama arose from tales inserted in the intervals of the dance. In Attic tragedy, the khoros (of 12 or 15 (tragic) or 24 (comedic) persons) gave expression, between the acts, to the moral and religious sentiments evoked by the actions of the play. English 16c. theater adopted a stripped-down version of this.
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]
The meaning "an organized company of singers" is from 1650s. Meaning "the refrain of a song" (which the audience joins in singing) is from 1590s; that of "a song to be sung by a (large) chorus" is from 1744. Meaning "main part of a modern popular song" (as distinguished from the verse, q.v.) is by 1926, originally in jazz. As a verb, 1703, from the noun. Chorus girl "young woman who sings and dances in a stage chorus" is by 1852.
early 15c., "company of soldiers, band of warriors," from French cohorte (14c.) and directly from Latin cohortem (nominative cohors) "enclosure," with meaning extended to "infantry company" in the Roman army through the notion of "enclosed group, retinue;" from assimilated form of com "with" (see co-) + a root akin to hortus "garden," from PIE *ghr-ti-, from PIE root *gher- (1) "to grasp, enclose."
Sense of "accomplice" is first recorded 1952, American English, from meaning "group united in common cause" (1719). In demographics, "group of persons having a common statistical characteristic" (originally being born in the same year), 1944.