part song

A part-song is a composition for two or more voices, (usually four) to be sung a capella.

Part-song was simplified, and Johan Walther compiled a hymnal of religious songs in the vernacular for from four to six voices.

The sanction of the cardinals was given—and part-song harmony became permanently one of the angel voices of the Christian church.

Suddenly, from a grove behind us, came the sound of children's voices singing an old German part-song.