A religious sister in the Catholic Church is a woman who has taken public vows in a religious institute dedicated to apostolic works, as distinguished from a nun who lives a cloistered monastic life dedicated to prayer and labor, or a canoness regular, who provides a service to the world, either teaching or nursing, within the confines of the monastery. Nuns, religious sisters and canonesses all use the term "Sister" as a form of address.
The former Superior General of the Sisters of Providence of Saint Mary-of-the-Woods, Sister Ann Margaret O'Hara, SP, in 2006. In the background a painting of the congregation's foundress, Mother Théodore Guérin.
Sisters (with chaplain) working at Mother of Peace AIDS orphanage in Zimbabwe, to prepare for opening another orphanage
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.
St. Scholastica, sister of St. Benedict and founder of the Benedictine nuns
Hildegard of Bingen and her nuns
Maria Johanna Baptista von Zweyer, Abbess of the Cistercian abbey of Wald
Three Sisters of Charity of St. Vincent de Paul in the Portal of a Church, by Armand Gautier
