A nun is a woman who vows to dedicate her life to religious service and contemplation, typically living under vows of poverty, chastity, and obedience in the enclosure of a monastery or convent. The term is often used interchangeably with religious sisters who do take simple vows but live an active vocation of prayer and charitable work.

A monastery is a building or complex of buildings comprising the domestic quarters and workplaces of monastics, monks or nuns, whether living in communities or alone (hermits). A monastery generally includes a place reserved for prayer which may be a chapel, church, or temple, and may also serve as an oratory, or in the case of communities anything from a single building housing only one senior and two or three junior monks or nuns, to vast complexes and estates housing tens or hundreds. A monastery complex typically comprises a number of buildings which include a church, dormitory, cloister, refectory, library, balneary and infirmary, and outlying granges. Depending on the location, the monastic order and the occupation of its inhabitants, the complex may also include a wide range of buildings that facilitate self-sufficiency and service to the community. These may include a hospice, a school, and a range of agricultural and manufacturing buildings such as a barn, a forge, or a brewery.