ADOPT v.
To take by choice into relationship, as, child, heir, friend, citizen, etc. ; esp. to take voluntarily (a child of other parents) to be in the place of, or as, one's own child.
AFFINITY n. 4 definitions
Relationship by marriage (as between a husband and his wife's blood relations, or between a wife and her husband's blood relations); -- in contradistinction to consanguinity, or relationship by blood; -- followed by with, to, or between. Solomon made affinity with Pharaoh. 1 Kings iii. 1.