Sister (title)
Sister was a title used by female members of some religious orders, such as nuns. 

In 1930, Sister Edith Keeler ran a soup-kitchen out of the . ()

In 2376, Dala pretended to be a cleric with the rank of sister as part of a swindle perpetrated on Neelix and Tom Paris. ()

See also 
 Sisterboy
 Sisters of Hope Infirmary

Religious titles