chorus (in music)
chorus, in music, large group of singers performing in concert; a group singing liturgical music is a choir. The term chorus may also be used for a group singing or dancing together in a musical or in ballet. By extension it can also mean the refrain of a song. Choral music stems from religious and folk music, both usually having interspersed singing. The chorus as a musical form is integral to opera, and since the 19th cent. it has also been integrated into compositions such as the symphony. Some modern choral groups, such as the Welsh singers, groups presenting spirituals, and the Don Cossack singers, continue the folk-chorus tradition. Others are intentionally formed to present all sorts of group vocal works. Choral societies grew numerous in the 19th cent., especially in Great Britain, the United States, and Germany. Some are created for special purposes, such as festival choruses, many oratorio societies, social and school groups (including glee clubs), and the Bach Choir of Bethlehem, Pa. In the United States, two men who did much to promote choral singing in the 19th cent. were William Billings and Theodore Thomas. After 1940 there was a marked increase in the popularity of choral groups, usually organized for stage performance; some of these specialize in concert versions of opera.