A religious is, in the terminology of many Western Christian denominations, such as the Catholic Church, Lutheran Churches, and Anglican Communion, what in common language one would call a "monk" or "nun".

A religious order is a lineage of communities and organizations of people who live in some way set apart from society in accordance with their specific religious devotion, usually characterized by the principles of its founder's religious practice. It is usually composed of laypeople and, in some orders, clergy. Such orders exist in many of the world's religions.