brother-in-law

[ bruhth-er-in-law ]

noun

, plural broth·ers-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

"It was only my father, my brother-in-law and our pastor who went in and put him in the coffin."

From BBC

Her husband was in left field; her brother-in-law was also on the team.

From Los Angeles Times

Five years earlier, her brother-in-law, President John F Kennedy, was assassinated in Dallas, Texas.

From BBC

The service was for the late Lord Robert Fellowes, brother-in-law of Princess Diana, on the Spencer side of the family, to which Prince Harry seems to have remained well connected.

From BBC

The Prince of Wales and Duke of Sussex both attended a memorial service for their mother’s brother-in-law Lord Robert Fellowes on Thursday.

From BBC

Related Words

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