The choir is where the priest and/or a choral group sings the psalms.

Outside, somewhere, the three young priests were singing hymns in distracted, drunken harmony.

And of late the cursed priests of Asura sing the same song.

A priest and the choir sang a verse of a hymn, each singing alternate lines in turn.

The priests and missionaries sing music akin to Gregorian chant.

The old priests sang songs and did ceremonies to keep him awake.

Again the priest sings another line of the song which the others repeat in chorus and thus it goes on.

The more the priests prayed and sang, the more the demon raged.

"I thought all of Lady Luck's priests sang that prayer each night."

With so many people dying, they need extra priests to sing all the souls to the other side.