brother-in-law

[bruhth-er-in-law]

noun

plural

brothers-in-law 

1. the brother of one's spouse.

2. the husband of one's sister or brother.

3. the husband of one's spouse's sister or brother.

brother-in-law

noun

1. the brother of one's wife or husband

2. the husband of one's sister

3. the husband of the sister of one's husband or wife

Word History and Origins

Origin of brother-in-law¹

First recorded in 1350–1400; Middle English brother in law(e); brother, in, law ¹; from Middle English in-lawe “in law,” i.e., “a person within the regulation and protection of the law,” based on the prohibition by Roman civil law and, later, Christian canon law, of marriages within four degrees of consanguinity, i.e., up to and including first cousins

Example Sentences

I’ve been asking my brother-in-law how much I owe him, but he’s such an amazing human being.

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He then started his own transportation company with his father and brother-in-law, working with the U.S. military and Western embassies in Kabul.

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The pothole stays because fixing it requires a municipal bond issue, three committee hearings and a contractor whose brother-in-law knows a guy.

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‘I’m worried about hurt feelings’: I regret hiring my brother-in-law as my financial adviser.

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Related: ‘I’m worried about hurt feelings’: I regret hiring my brother-in-law as my financial adviser.

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Related Words

• aunt 
• cousin 
• father 
• folk 
• mother 
• niece 
• sibling 
• uncle