シスター (shisutā) means “nun” | MotiTan Japanese Dictionary

More examples

そのシスターは子どもたちに聖書を教えています。so no shi su tā wa ko do mo ta chi ni sei sho o oshi e te i ma su

That nun teaches the children the Bible.

Refers to a woman who belongs to a Christian religious community and is regarded as a sister within it, typically as a nun.

修道女shūdōonna: A woman who belongs to a Christian religious order and lives according to its religious rules.

キリスト教の修道会で共同生活をし、信仰に基づいて活動する女性。ki ri su to kyō no shū dō kai de kyō dō sei katsu o shi shin kō ni moto zu i te katsu dō su ru jo sei

シスター (shisutā) is a loanword from English sister, whose religious sense applies the family term to a woman in a religious community.

English speakers may recognize sister as a title for a nun in phrases such as Sister Mary, while its everyday meaning is usually female sibling.