In the Eastern Orthodox and Byzantine Catholic Churches, the canonical hours may be referred to as the divine services, and the book of hours is called the horologion ( Greek: Ὡρολόγιον).
In Lutheranism and Anglicanism, they are often known as the daily office or divine office, to distinguish them from the other 'offices' of the Church (e.g. The current official version of the hours in the Roman Rite is called the Liturgy of the Hours ( Latin: liturgia horarum) or divine office. In the Roman Rite of the Catholic Church, canonical hours are also called officium, since it refers to the official prayer of the Church, which is known variously as the officium divinum ('divine service' or 'divine duty'), and the opus Dei ('work of God'). A book of hours, chiefly a breviary, normally contains a version of, or selection from, such prayers. In the practice of Christianity, canonical hours mark the divisions of the day in terms of fixed times of prayer at regular intervals.
Opening versicle Domine labia mea aperies et os meum annuntiabit laudem tuam from a book of hours, ca. For the specific manifestation of the canonical hours in the public prayer of the Roman rite of the Catholic Church, see Liturgy of the Hours.