[sib] adj [ME, fr. OE sibb, fr. sibb kinship; akin to OHG sippa kinship, family, L sodalis comrade, Gk ethos custom, character, L suus one's own--more at suicide] (bef. 12c): related by blood: akin
[2]sib n (bef. 12c) 1 a: kindred, relatives b: a blood relation: kinsman
2: a brother or sister considered irrespective of sex; broadly: any plant or animal of a group sharing a degree of genetic relationship corresponding to that of human sibs
3: a group of persons unilaterally descended from a real or supposed ancestor