1. A choir is called a chorus in the opera house and musical theatre. Also when it is attached to an orchestra. It tends to be associated with professional singing ensembles.
2. A work written for choir, or other ensemble of singers who are not soloists.
3. The final section of a stanza in a song or hymn sung by the full choir or the congregation. It follows the verse which is sung by a soloist or soloists.
