In the Roman Catholic tradition, there are many religious institutes of nuns and sisters (the female equivalent of male monks or friars), each with its own charism or special character. Traditionally, nuns are members of enclosed religious orders and take solemn religious vows, while sisters do not live in the papal enclosure and formerly took vows called "simple vows".
Free Download Below
Nun flickr photo by mapuna shared under a Creative Commons (BY) license
"Nun" flickr photo by mapuna https://flickr.com/photos/anupamsr/412708403 shared under a Creative Commons (BY) license