The Liturgy of the Hours (Latin: Liturgia Horarum) or Divine Office (Latin: Officium Divinum) or Work of God (Latin: Opus Dei) or canonical hours, often referred to as the Breviary, is the official set of prayers "marking the hours of each day and sanctifying the day with prayer". It consists primarily of psalms supplemented by hymns, readings and other prayers. Together with the Mass, it constitutes the official public prayer life of the Church. The Liturgy of the Hours also forms the basis of prayer within Christian monasticism.