The Liturgy of the Hours (Latin: Liturgia Horarum), Divine Office (Latin: Officium Divinum), or Opus Dei ("Work of God") are a set of Catholic prayers comprising the canonical hours,often also referred to as the breviary,of the Roman Catholic Church. The Liturgy of the Hours forms the official set of prayers "marking the hours of each day and sanctifying the day with prayer." The Liturgy of the Hours, like many other forms of the canonical hours, consists primarily of psalms supplemented by hymns, readings, and other prayers and antiphons prayed at fixed prayer times. Together with the Mass, it constitutes the public prayer of the church.