Chorale
Unaccompanied liturgical chant (Gregorian chant) or a Lutheran hymn tune.
What it means
The German word “Choral” carries two related meanings, both rendered differently in English. One is Gregorian chant, the unaccompanied, monophonic liturgical singing of the Roman Catholic Church transmitted since the early Middle Ages. The other is the Lutheran chorale, the congregational hymn tune sung since the Reformation, especially through Martin Luther, usually set in four parts with a fixed strophic melody.
The two senses are historically linked: the Reformation hymn replaced Latin liturgical chant and took over its role in worship, now sung in the vernacular and with a simpler rhythm.
Musical use
Gregorian chant forms the foundation of Catholic liturgy for centuries and the starting point for Western notation and polyphony. The Lutheran chorale, in turn, became the seed for many forms: the chorale prelude and chorale cantata of organ and cantata music, and the many four-part chorale harmonizations written by Johann Sebastian Bach.
Both should be distinguished from free church music without a fixed strophic tune, and from secular song: a chorale is always tied to a liturgical or sacred context.
Performance practice
When singing Gregorian chant, follow its flowing, text-driven rhythm without a fixed meter. When singing a Lutheran chorale, keep the tune clear and steady so a whole congregation can join in.