White Sister
noun
A nun belonging to an order which wears a white habit; (in later use) specifically a member of the Congregation of the Missionary Sisters of Our Lady of Africa, founded in 1869 to assist the White Fathers, or of the Congregation of the Daughters of the Holy Ghost, founded in 1706 in Brittany.
Origin
Early 17th century; earliest use found in Edward Grimeston (fl. 1604–1634), translator.