Affinitas affinitatis

AFFINITAS AFFINITATIS. That connexion between two persons which has neitherconsanguinity nor affinity; as, the connexion between the husband's brotherand the wife's sister. This connexion is formed not between the partiesthemselves, nor between one of spouses and the kinsmen of the other, butbetween the kinsmen of both. Ersk. Inst. B, 1, tit. 6, s. 8.