Christian liturgy is a pattern for worship used (whether recommended or prescribed) by a Christian congregation or denomination on a regular basis. The term liturgy comes from Greek and means "public work". Within Christianity, liturgies descending from the same region, denomination, or culture are described as ritual families or rites.
When Christians meet for worship, they perform a liturgy (work), offering service to God together. The majority of Christian denominations hold their principal church service on Sunday, the first day of the week, which is known as the Lord's Day.