Courtesy of Google Alerts I learned that there has been some inquiry and discussion in the blogosphere about the difference between nuns and sisters. We commonly use the terms interchangeably but technically they are very different. Yes, nuns are contemplatives whose life centers around prayer in the monastery usually under the regulations of Papal Enclosure. These may also be called cloistered nuns. We like to use the phrase contemplative monastic.
The technical difference between a nun and a sister is that nuns, usually belonging to an order, take solemn vows of poverty chastity and obedience. Sisters, on the other hand take simple vows of poverty, chastity and obedience and usually belong to congregations. So in Canon Law of the Roman Catholic Church the words nun, sister, solemn, simple, order and congregation have very specific definitions. The greatest difference between solemn and simple vows, as I understand it, seems to come in the vow of poverty. If a sister in a congregation, like the Sisters of St. Joseph and others, who has taken simple vows should inherit money, that money is held in the treasury of her congregation. The principle cannot be touched without her permission. The interest may be used by the congregation and she may suggest uses for it. She may even request the use of some of the money for herself. Should she leave the congregation, any interest accrued remains with the congregation but the principle goes with her. This is called her patrimony. If a nun in solemn vows should inherit money or property it must go directly to her community. Should she leave the order she will not receive any of those funds. They have become the property of the monastery. Another way to think about this is that any vowed religious in an order is a nun and in solemn vows. Any religious under simple vows in a congregation is a sister. At one time in history political authorities in Europe banned solemn vows for religious because monasteries were becoming too wealthy as hey incorporated doweries and inheritances into their holdings.
To carry this out further, an order is usually composed of autonomous monasteries in which the superior, a prioress or abbess, has the authority equivalent to that of the general superior of a congregation of sisters. Therefore, among other things, a prioress or abess can dispense a nun from first vows (before solemn vows) without consulting any other authority. A sister asking for dispensation from first vows must go beyond her local superior to the general superior of her congregation.
Was that enough canonical trivia for you?