sister

A sister is a female who shares at least one parent with another person. The term can denote a biological sibling, a female relative by adoption, or a broader social bond that resembles kinship. In many cultures, sisterhood conveys a close, supportive relationship among women.

Biologically, sisters may be full, sharing both parents, or half, sharing one. Stepsisters or adoptive sisters can form sisterly ties without a genetic link. Kinship terms and rights vary by culture, including custody arrangements, inheritance, and family structure.

Culturally and institutionally, "sister" serves as a title or term of address. In religious communities, nuns may be called Sisters. The word appears in phrases such as sister city, sister church, or sister organization to denote close cooperation between groups.

Etymology: The English word sister derives from Old English sweostor, from Proto-Germanic roots; cognates include German Schwester and Dutch zuster. The exact Indo-European origin is uncertain, but related terms appear across many languages to denote a female sibling.

Related terms include sister-in-law, stepsister, and phrases like sister city, reflecting both family and cooperative relationships.