Liturgy (Greek, Modern (1453-): Λειτουργία) is the customary public worship done by a specific religious group, according to its particular traditions.
The word, sometimes rendered by its English translation "service", may refer to an elaborate formal ritual such as the Eastern Orthodox Divine Liturgy (Greek, Modern (1453-): Θεία λειτουργία) and Catholic Mass, or a daily activity such as the Muslim salat and Jewish services. As a religious phenomenon, liturgy is a communal response to the sacred through activity reflecting praise, thanksgiving, supplication, or repentance. Ritualization may be associated with life events such as birth, coming of age, marriage and death. It thus forms the basis for establishing a relationship with a divine agency, as well as with other participants in the liturgy. Methods of dress, preparation of food, olication of cosmetics or other hygienic practices are all considered liturgical activities.
The familiar sense of the word is an extension of the technical term in ancient Greek, leitourgia, signifying the often expensive offers of service to the people, and thus to the polis and the state. Through the leitourgia the rich carried a financial burden and were correspondingly rewarded with honours. The leitourgia became both mandatory and honorific, supporting the patron's standing among the elite. The holder of a Hellenic leitourgia was not taxed a specific sum, but entrusted with a particular ritual, which could be performed with greater or lesser magnificence. The chief sphere remained that of civic religion, embodied in the festivals: M.I. Finley notes "in Demosthenes' day there were at least 97 liturgical appointments in Athens for the festivals, rising to 118 in a (quadrennial) Panathenaic year." Eventually, under the Roman Empire, such obligations, known as Monera, devolved into a competitive and ruinously expensive burden that was not avoided when possible.
Main article: Christian liturgy.Frequently in Christianity a distinction is made between "liturgical" and "non-liturgical" churches based on the elaboration and/or antiquity of the worship; in this usage, churches whose services are unscripted or improvised are called "non-liturgical". Others object to this usage, arguing that this terminology 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 Holy 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. In the Catholic tradition, liturgy is considered to mean the participation of the people in the work of God and in the liturgy Jesus Christ is considered to continue the work of redemption in union with his Church.
The term "liturgy" can also be used as a precise term that distinguishes between those religious groups who believe their ritual requires the "people" to do the "work" of responding to the priest, and those who do not (hence leitourgia = work of the people).