A Christian liturgy is a set of steps or rituals done by Christians as a form of worship, done by Christian denomination. The liturgy or form of worship has changed over time, and different groups also have different prescriptions on how such a celebration should be done. The worship on a Sunday might be different from that which is done on Easter.
Anglican, Orthodox, Lutheran, or other groups, when using the words "the liturgy", normally mean a standardized order of events observed during a religious service, often including the Eucharist or Communion. Liturgy may mean an elaborate formal ceremony such as the Catholic Mass. The open or waiting worship of Quakers is an example of a non-liturgical service because there is no structured order of events.
Liturgical churches are those that use a well-defined liturgy, in which many of the words and music used follow basic patterns each time the service is conducted. The liturgy may date to the second century or earlier. Most Orthodox, Catholic, Anglican, and Lutheran churches are liturgical, most other churches to a far lesser extent. Non-liturgical churches usually follow a common worship sequence from one service to the next, with several elements common to many such services. These elements often include readings from the Bible, hymns, a sermon, offerings of money, and at certain times, Communion.
- Oxford Dictionary of World Religions, p.582-3)