sib

[sib] /sɪb/
adjective
1.
related by blood; akin.
noun
2.
a kinsman; relative.
3.
one's kin or kindred.
4.
Anthropology. a unilateral descent group.
Origin
before 900; Middle English sib(e), sibb(e), Old English sib(b) (orig. adj.); cognate with Old Norse sifjar (plural) relatives, Old Frisian sib (adj.), sibba (noun), Middle Dutch sibbe (noun and adj.), German Sippe kin; cf. gossip
British Dictionary definitions for sib

sib

/sɪb/
noun
1.
a blood relative
2.
a brother or sister; sibling
3.
kinsmen collectively; kindred
4.
any social unit that is bonded by kinship through one line of descent only
Word Origin
Old English sibb; related to Old Norse sifjar relatives, Old High German sippa kinship, Latin suus one's own; see gossip

SIB

abbreviation (in Britain)
1.
(the former) Securities and Investments Board
Word Origin and History for sib
n.

short for sibling, attested from 1957.

sib in Medicine

sib (sĭb)
n.

  1. A blood relation; a relative.

  2. A person's relatives when considered as a group; kinfolk.

  3. A brother or sister; a sibling.

adj.
Related by blood; kindred.