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 it was utilised in a way that aided the study of genetics, which 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.
- → English: sibling
- sibling in Joseph Bosworth and T. Northcote Toller (1898) An Anglo-Saxon Dictionary