1903, modern revival of Old English sibling (“relative, a relation, kinsman”), equivalent to sib + -ling. Compare Middle English sib, sibbe (“relative; kinsman”), German Sippe. The term apparently meant merely kin or relative until the 20th century when its necessity for the study of genetics led to its specialized use. For example, the OED has a 1903 citation in which "sibling" must be defined for those who don't know the intended meaning.
sibling (plural siblings)
- A person who shares a parent; one's brother or sister who one shares a parent with.
- None of my siblings are married yet.
- (computing theory) A node in a data structure that shares its parent with another node.