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.
Easton’s Bible Dictionary
Affinity
Easton’s Bible Dictionary (1897), public domain. Text via Theographic Bible Metadata, CC BY-SA 4.0.