Note:  Do not rely on this information. It is very old.

Affinity Legal

Affinity (Legal), in contradistinction to consanguinity, the term denoting the relationship brought about by marriage between the husband or wife and the blood relations of either. But this relationship is personal to the husband and wife respectively, and does not extend so far as to bring into affinity the blood relations of one with those of the other: thus a wife's sister has no affinity with her husband's brother.