brother-in-law

noun

broth·​er-in-law ˈbrə-t͟hər-ən-ˌlȯ 

ˈbrət͟h-rən-,

ˈbrə-t͟hərn-

plural brothers-in-law ˈbrə-t͟hərz-ən- 

1

: the brother of one's spouse

2

a

: the husband of one's sibling

b

: the husband of one's spouse's sibling

Examples of brother-in-law in a Sentence

Recent Examples on the Web

His sister Yingluck ran a government until a court ruling ended her tenure followed by a 2014 military coup, while Thaksin’s brother-in-law was also in charge of Thailand briefly during his absence. —Helen Regan, CNN Money, 9 Sep. 2025

Martin Langesfeld, who lost his sister and brother-in-law in the building collapse, told members of the committee Tuesday afternoon that the investigation into the tragedy has taken too long. —Jared Kofsky, ABC News, 9 Sep. 2025

From her Granny and Pappy to her mom, dad, sister, soon-to-be brother-in-law, uncles, aunts and cousins – everyone took part. —Tereza Shkurtaj, PEOPLE, 7 Sep. 2025

The series was created by Julie Puckrin and inspired by her sister and brother-in-law, who met flying air ambulances. —Rosy Cordero, Deadline, 2 Sep. 2025

Word History

First Known Use

14th century, in the meaning defined at sense 1

Rhymes for brother-in-law

• avoirdupois
• aa
• aha
• bashaw
• bradshaw
• byelaw
• bylaw
• chainsaw
• cheraw
• coleslaw
• crenshaw
• dada

Kids Definition

brother-in-law

noun

broth·​er-in-law

ˈbrət͟h-(ə-)rən-ˌlȯ,

ˈbrət͟h-ərn-ˌlȯ

plural brothers-in-law

ˈbrət͟h-ər-zən-

1

: the brother of one's spouse

2

: the husband of one's sibling or of one's spouse's sibling