- The definition of a sibling is a person who shares the same parents as you.
An example of a sibling is the little boy born to your mother and father right after you. He is your brother and your sibling.
Origin of sibling20th-c. revival of Old English a relative: see sib and amp; -ling
Origin of siblingMiddle English, from Old English, from sibb, kinsman; see sib.
1903, modern revival of Old English sibling (â€œrelative, a relation, kinsmanâ€), equivalent to sib +â€Ž -ling. Compare Middle English sib, sibbe (â€œrelative, kinsmanâ€). 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.
- "1903 K. PEARSON in Biometrika II. 369 These [calculations] will enable us..to predict the probable character in any individual from a knowledge of one or more parents or brethren (â€˜siblingsâ€™, = brothers or sisters)." ("Sibling," OED.)