Merriam-Webster Online Dictionary
sister (noun)1.
a female who has one or both parents in common with another
2.
often capitalized
a) a member of a women's religious order (as of nuns or deaconesses) , especially one of a Roman Catholic congregation under simple vows
b) a girl or woman who is a member of a Christian church
3.
a) a girl or woman regarded as a comrade
b) a girl or woman who shares with another a common national or racial origin , especially a black girl or woman
4.
one that is closely similar to or associated with another - sister cities
5.
chiefly British - nurse
6.
a) - girl woman
b) - person usually used in the phrase weak sister
7.
a member of a sorority
