ˈbrəthə(r)ə̇nˌlȯ, -thrə̇n-, -thə(r)n- noun
( plural brothers-in-law -thə(r)zə̇n-)
Etymology: Middle English brother in lawe; probably from the fact that the canon law forbids marriage with one's spouse's sister or brother
1. : the brother of one's spouse — compare affinity
2. : the husband of one's sister ; broadly : the husband of one's spouse's sister