Definition of 'sister'
- a female person who has the same parents as another person; "my sister married a musician"
Antonyms: brother blood brother
- (Roman Catholic Church) a title given to a nun (and used as a form of address); "the Sisters taught her to love God"
- a female person who is a fellow member of a sorority or labor union or other group; "none of her sisters would betray her"
- (slang) sometimes used as a term of address for attractive young women