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

An introduction from his brother-in-law led to a job with a company selling mortgages.

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But the vital factor in his success was having a rich and credulous brother-in-law.

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He was also convicted of a second count of wounding with intent for attacking his new brother-in-law, Hasan Khan, with a knife following the crash, stabbing him repeatedly in the head and chest.

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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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Related Words

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