affine

The element of personal idiosyncracy may be expected to be most marked in regard to affines (i.e. those related by marriage) and particularly with the consanguines of affines, who are linked by still more tenuous bonds. There are many possible degrees of affinal relationship here, but broadly affines separate into two main types: spouse of consanguine of Ego, and consanguine of spouse of Ego—exemplified by my brother's wife, and my wife's brother.