n.1 a regular group of singers, esp. taking part in church services.
2 the part of a cathedral or large church between the altar and the nave, used by the choir and clergy.
3 a company of singers, birds, angels etc. (a heavenly choir).
4 Mus. a group of instruments of one family playing together.
Phrases and idioms:
choir organ the softest of three parts making up a large organ having its row of keys the lowest of the three. choir-stall STALL(1) n. 3a.
Etymology: ME f. OF quer f. L chorus: see CHORUS