What term is used to describe individuals having one or both parents in common?

The term used to describe individuals who share one or both parents in common is "siblings." Siblings can be full siblings, sharing both parents, or half-siblings, sharing only one parent. This familial relationship signifies a direct blood connection, distinguishing it from other terms like cousins, who share grandparents but not immediate parents, or relatives, which is a broader term that includes all family members. "Flatmates," on the other hand, refers to individuals living together without necessarily any familial ties. Understanding these distinctions is crucial in discussions related to family relationships and legal terminology involved in matters such as inheritance, custody, and other familial legal issues.