Definitions
1.NounA group of people who sing together; a company of people who are trained to sing together."The church choir practices Thursday nights."
2.NounOne quarter of a cruciform church, or the architectural area of a church, generally used by the choir; often near the apse.
3.NounOne of the nine ranks or orders of angels."Seraphim, Cherubim, and Thrones are three of the choirs of angels."
4.NounSet of strings (one per note) for a harpsichord.
5.VerbTo sing in concert.