Easton's Bible Dictionary (1897)
Relationship by alliance (2 Chr. 18:1) or by marriage (1 Kings 3:1). Marriages are prohibited within certain degrees of affinity, enumerated Lev. 18:6-17. Consanguinity is relationship by blood.
Smith's Bible Dictionary (1863)
[Marriage]
Hastings' Dictionary of the Bible (1898) & Schaff's Bible Dictionary
AFFIN'ITY. 1 Kgs 3:1. Relation by marriage, in contradistinction from consanguinity, which is relation by birth. The degrees of affinity which should prevent marriage under the Mosaic law may be found in Lev 18:6-17. See Marriage.