sibling

sibling
    n 1: a person's brother or sister [syn: {sibling}, {sib}]
    

sibling \sib"ling\ [sub + -ling.] (s[i^]b"l[i^]ng), n.
   a brother or a sister.

   Note: Siblings have at least one parent in common. Those
         related only by a common mother are {uterine siblings};
         those related only by a common father are {agnate
         siblings} or {consanguine siblings} (a legal term). A
         sibling having both parents in common is a
         {sibling-german} or a {full brother} or {full sister}.
         These modifying terms are more commonly used for the
         more specific {uterine brother}, {uterine sister},
         {agnate brother}, {brother-german}, etc.
         [PJC]
    

sibling \sib"ling\ (s[i^]b"l[i^]ng), a.
   of or pertaining to a {sibling}, n.; as, sibling rivalry: the
   common rivalry between siblings.
   [PJC]
    

63 Moby Thesaurus words for "sibling":
      affiliated, agnate, akin, allied, ancestry, avuncular, blood,
      blood relation, blood relative, clansman, closely related, cognate,
      collateral, collateral relative, congeneric, connections,
      consanguine, consanguinean, consanguineous, distaff side,
      distant relation, distantly related, enate, family, flesh,
      flesh and blood, folks, foster, german, germane, kin, kindred,
      kinfolk, kinnery, kinsfolk, kinsman, kinsmen, kinswoman,
      kith and kin, matrilateral, matrilineal, matroclinous,
      near relation, next of kin, novercal, of the blood, patrilateral,
      patrilineal, patroclinous, people, posterity, related, relations,
      relatives, sib, spear kin, spear side, spindle kin, spindle side,
      sword side, tribesman, uterine, uterine kin