definition of
Sister

[1] #1 Sister n. [sister, sis] a female person who has the same parents as another person; "my sister married a musician". wn

[2] #2 Sister n. (Roman Catholic Church) a title given to a nun (and used as a form of address); "the Sisters taught her to love God". wn

[3] #3 Sister n. [sister] a female person who is a fellow member of a sorority or labor union or other group; "none of her sisters would betray her". wn

[4] #4 Sister n. [baby, babe, sister] (slang) sometimes used as a term of address for attractive young women. wn