A liturgy is the customary public worship one by a specific religious group, according to their particular traditions. The word may refer to an elaborate formal ritual such as the Eastern Orthodox Divine Liturgy or Catholic Mass, or a daily activity such as the Muslim salat (see Oxford Dictionary of World Religions, p.582–3). Not infrequently in Christianity, a distinction is made between "liturgical" and "non-liturgical" churches based on the elaboration and/or antiquity of the worship, but this obscures the universality of public worship as a religious phenomenon. Thus, even the open or waiting worship of Quakers is liturgical, since the waiting itself until the spirit moves individuals to speak is a prescribed form of Quaker worship, sometimes referred to as "the liturgy of silence." Typically in Christianity, however, the term "the liturgy" normally refers to a standardized order of events observed during a religious service, be it a sacramental service or a service of public prayer.