Available Definitions:
1) n. - A female who has the same parents with another person, or who has one of them only. In the latter case, she is more definitely called a half sister. The correlative of brother.
2) n. - A woman who is closely allied to, or assocciated with, another person, as in the sdame faith, society, order, or community.
3) n. - One of the same kind, or of the same condition; -- generally used adjectively; as, sister fruits.
4) v. t. - To be sister to; to resemble closely.