halfsister

A half-sister is a female who shares one biological parent with another person. This distinguishes her from a full sister, who shares both parents, and from a stepsister or adoptive sister, who may not share any biological parent.

The shared parent may be the mother or the father. The other parent is different for each person.

Genetic relatedness: On average, half-siblings share about 25% of their genetic material, though this can vary. The exact amount depends on how the shared parent's genes are inherited by each child.

In social and legal terms, the term is used in family and genealogical contexts. Rights, responsibilities, and procedures related to inheritance, custody, or succession differ by jurisdiction and individual circumstances, and are not determined by the term alone.

Etymology and usage: "half" indicates sharing one parent. Some people use maternal half-sister or paternal half-sister to specify which parent is shared; in other languages the term may differ.

In genealogical charts, a half-sister is depicted as two individuals connected to a common parent by one edge, illustrating the single shared parent in their lineage.