Liturgy is a term that refers to the prescribed order of worship used in many religions and churches. Certain Christian denominations follow a standard form of worship for their services which normally includes hymn singing, prayers, scripture readings, responsive readings, a creedal statement, the sermon, a confession of sins, Holy Communion, and a formal dismissal. Other denominations do not use the historic order of worship and are more spontaneous in their worship practices. These are called "non-liturgical" churches. They include the Baptist and Pentecostal churches and most non-denominational ones.
Churches in which a version of the traditional liturgy is used—such as the Eastern Orthodox, Roman Catholic, High Church Anglican, Lutheran, Methodist, Reformed and Presbyterian churches—are classified as "liturgical" in worship. In some of them the liturgical service is styled the Mass, a word that invokes the concept of the service as a ceremonial offering of a sacrifice to God.
The liturgy is sometimes set forth according to a book used by the congregation at worship. Examples are the Book of Common Prayer in the Anglican and Episcopal churches, Missals used by the Catholic churches, and Lutheran Service Books.