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Nuns from WikiPedia:

A nun, or also known as a sister in some cases, is a woman who has taken special vows committing her to a religious life. She may be an ascetic who voluntarily chooses to leave mainstream society and live her life in prayer and contemplation in a monastery or convent. The term "nun" is applicable to the Catholics (both eastern and western traditions), Eastern Orthodox, Anglicans, Lutherans, Jains, Buddhists, and Taoists, for example. While in common usage the terms nun and sister are often used interchangeably, properly speaking a nun is a female religious who lives a contemplative life of prayer and meditation within a monastery while a sister (in the Christian religions) lives an active vocation of service to the needy, sick, poor, and uneducated.

In the Catholic Church, a nun is a female monastic who has taken solemn vows (the male equivalent is often called a "monk", although the positions actually entail very different religious origins and constitute very different duties within the church). Nuns are cloistered to the degree established by the rule of the religious institution they enter.

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