Sister SVG is a girl/woman in relation to another child(s) of her parents:
Older sister is a girl/woman in relation to the younger child(s) of her parents.
The younger sister is a girl/woman in relation to her parents’ older child(s).
Sisterhood is a relationship between two parents who remarry between their children from previous marriages. In other words, the stepbrothers/sisters do not share the same parents and are linked by a family relationship, but not by biological kinship.