f., pl. sifjar; [Ulf. sibja. Gal. iv. s. Rom. ix. 4; A. S. and Scot. sib; Engl. gos-sip = god-sib; Hel. sibbia; O. H. G. sibba; Germ. sippe]:—affinity.

2. in sing. the word is only used as a pr. name ot the goddess Sif, gen. sifjar (dat. sifju, Edda i. 340). Sif, the golden-haired goddess, wife of Thor, betokens mother earth with her golden sheaves of grain; she was the goddess of the sanctity of the family and wedlock, whence her name, see Edda and the old poems passim.

3. plur. ‘sib’, affinity, connection, by marriage; the word is used in ancient poems and in the law, and in compds; byggja sifjar, to marry; jafnnáit skal byggja sifjar ok frændsemi, Grág. i. 308; eigi skulu vera skyldri sifjar með þeim enn fimmta manni, i. e. no marriage nearer than the fifth degree, 310; sifjar (affinity) is opp. to frændsemi (blood relationship), flest stórmenni var bundit í frændsemi eða sifjum við hann, Fms. vii. 299, v. l.; spilla sifjum, to commit adultery; munu systrungar sifjum spilla, cousins will ‘spoil the sib,’ referring to adulterous intercourse with near relations in law, Vsp.; slíta sifjum = spilla sifjum, Merl. 154: again, þyrma sifjum, to hold the sifjar holy, Skv. 3. 28: hence sifja-slit and sifja-spell, n. pl. violation of the law of affinity, adultery; frændsemis-spell ok sifja-spell, Grág. i. 341, Sks. 338 B; þat eru sifjaslit en meiri, er maðr liggr með systrungum tveim, Grág. i. 358; í manndrápum ok í sifjasliti, Edda. The word sifjar also remains in bú-sifjar (q. v.), Landn. 147, Eg. 750, Fs. 31; guð-sifjar (q. v.), as also guð-sefi, guð-sifja (q. v.), a gossip, sponsor: in karl-sift, kvenn-sift, q. v.; cp. also barna sifjar, the bond or unity arising from having had children together, or = adoption (?), cp. Ulf. suniwe-sibja = υἱοθεσία, Gal. iv. 5, Ls. 16: lastly, the phrase, blanda sifjum, to blend sifjar together, to blend souls together (?), Hm. 125 (akin to sefi, q. v.)