- sibling, sib - a person's brother or sister
--1 is a kind of relative, relation
--1 is a member of family, family unit
--1 has particulars:half blood; quadruplet, quad; quintuplet, quint, quin; triplet; twin - blood relation, blood relative, cognate, sib - one related by blood or origin; especially on sharing an ancestor with another
--2 is a kind of relative, relation