religious sister

A religious sister (abbreviated: Sr.) is a Christian woman who has taken public vows in a religious order dedicated to apostolic works. Though often referred to as nuns, they are canonically distinct. Nuns, religious sisters and canonesses all use the term "Sister" as a form of address. Religious sisters are found in various traditions of Christianity, particularly Catholicism, Evangelical Lutheranism and Anglicanism. In the Catholic Church, religious sisters are associated with a religious institute.