stepsister

This term describes a specific familial relationship created by the marriage of a parent to another person who already has a daughter. It is distinct from a half-sister, who shares one biological parent with the individual. The prefix step- indicates a legal or social bond rather than a genetic one.

In modern usage, the term is neutral, though the emotional quality of the relationship varies widely depending on the family dynamic. It is used in both formal legal contexts and casual conversation to clarify kinship structures.