Nun different from religious sister
A nun is a woman who vows to dedicate her life to God, 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.
In Christianity, nuns are found in the Roman Catholic, Oriental Orthodox, Eastern Orthodox, Lutheran, and Anglican traditions, as well as other Christian denominations. In the Buddhist tradition, female monastics are known as Bhikkhuni, and take several additional vows compared to male monastics (bhikkhus). Nuns are most common in Mahayana Buddhism, but have more recently become more prevalent in other traditions.Distinction between a nun and a religious sister
Although usage has varied throughout church history, typically "nun" (Latin: monialis) is used for women who have taken "solemn" vows, and "sister" (Latin: soror) is used for women who have taken "simple" vows (that is, vows other than solemn vows).
During the first millennium, nearly all religious communities of men and women were dedicated to prayer and contemplation. These monasteries were built in remote locations or were separated from the world by means of a precinct wall. The mendicant orders, founded in the 13th century, combined a life of prayer and dedication to God with active works of preaching, hearing confessions, and service to the poor, and members of these orders are known as friars rather than monks. At that time, and into the 17th century, Church custom did not allow women to leave the cloister if they had taken religious vows. Female members of the mendicant orders (Dominican, Augustinian and Carmelite nuns and Poor Clares) continued to observe the same enclosed life as members of the monastic orders.Originally, the vows taken by profession in any religious institute approved by the Holy See were classified as solemn. This was declared by Pope Boniface VIII (1235–1303). The situation changed in the 16th century. In 1521, two years after the Fourth Lateran Council had forbidden the establishment of new religious institutes, Pope Leo X established a religious Rule with simple vows for those tertiaries attached to existing communities who undertook to live a formal religious life. In 1566 and 1568, Pope Pius V rejected this class of congregation, but they continued to exist and even increased in number. After at first being merely tolerated, they afterwards obtained approval. Finally in the 20th century, Pope Leo XIII recognized as religious all men and women who took simple vows. Their lives were oriented not to the ancient monastic way of life, but more to social service and to evangelization, both in Europe and in mission areas. Their number had increased dramatically in the upheavals brought by the French Revolution and subsequent Napoleonic invasions of other Catholic countries, depriving thousands of religious of the income that their communities held because of inheritances and forcing them to find a new way of living the religious life. But members of these new associations were not recognized as "religious" until Pope Leo XIII's Constitution "Conditae a Christo" of 8 December 1900.The 1917 Code of Canon Law reserved the term "nun" (Latin: monialis) for religious women who took solemn vows or who, while being allowed in some places to take simple vows, belonged to institutes whose vows were normally solemn. It used the word "sister" (Latin: soror) exclusively for members of institutes for women that it classified as "congregations"; and for "nuns" and "sisters" jointly it used the Latin word religiosae (women religious). The same religious order could include both "nuns" and "sisters", if some members took solemn vows and others simple vows.
The new legal code of the Catholic Church which was adopted in 1983, however, remained silent on this matter. Whereas previously the code distinguished between orders and congregations, the code now refers simply to religious institutes.
Since the code of 1983, the Vatican has addressed the renewal of the contemplative life of nuns. It produced the letter Verbi Sponsa in 1999, the apostolic constitution Vultum Dei quaerere in 2016, and the instruction Cor Orans in 2018 "which replaced the 1999 document Verbi Sponsa and attempted to bring forward the ideas regarding contemplative life born during the Second Vatican Council".