When you sing alone, there's no-one to take the pressure off you or give you a hand if you forget things or lose your thread.
glee clubs usually dance as well (show choir) and choir is just singing
A choir singing in alternation is when different groups or sections of the choir take turns singing parts of a song or piece of music.
Both are used, but "massed choir" removes the confusion with a choir singing a mass.
The saying is "Preaching to the choir."
When a vocalist sings by themselves as opposed to with a choir this is known simply as a 'solo'.
Choir/gospel choir
There will be a choir singing in church on Sunday.
The difference would be decided by the church's administration; Canons, Deacons, etc.
Verse choir is a type of choral singing where a soloist or a small group alternates verses with the full choir singing the refrain or chorus. This style allows for a dynamic interplay between the soloist and the choir, creating a contrast in texture and highlighting different voices within the ensemble. It is commonly used in religious music and hymns.
A Choir Director or professor.
This alternation between a cantor chanting psalm verses and a choir singing a refrain is known as responsorial psalmody. The cantor typically sings the verses of the psalm, while the choir or congregation responds with a repeated refrain. This form of singing is common in liturgical settings, such as during Mass or other religious services.
A 'Choir' are a group of singers singing songs. Therefore a church choir are those members of the congregation who come together to practice singing the church music so that they can lead the congregation in singing praises to god.