What term is used to describe a brother or sister?

The term "sibling" specifically refers to a brother or sister, signifying a direct relationship between individuals who share at least one parent. This term is commonly used in family and social studies to delineate this particular familial bond. Siblings may have varying relationships with one another, shaped by factors such as age, gender, and life experiences, but the term itself encapsulates the idea of shared lineage. This specificity in terminology is essential in understanding family dynamics and the roles individuals play within a household. In contrast, terms like "peer," "relative," and "family member" are broader and can encompass various relationships, making them less precise when defining a brother or sister.