Word Origin & History
"brother or sister," 1903, modern revival (in anthropology) of O.E. sibling "relative, kinsman," from sibb (adj.) "kinship, relationship" (1500; surviving as sib, chiefly in Scottish), from P.Gmc. *sebjo "blood relation, relative," prop. "one's own" (cf. O.S. sibba, O.Fris., M.Du. sibbe, O.H.G. sippa,
Ger. Sippe, Goth. sibja "kin, kindred"), from PIE s(w)e-bh(o)-, from base *swe- (see idiom
). Related to the second element in gossip
"The word 'sib' or 'sibling' is coming into use in genetics in the English-speaking world, as an equivalent of the convenient German term 'Geschwister' " [E.&C. Paul, "Human Heredity," 1930]
Short form sib is attested from 1957.