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

Built in 1887 for Charles Erhart, co-founder of the pharmaceutical giant Pfizer and brother-in-law to Charles Pfizer himself, the mansion has lived many lives since the Gilded Age. —Abby Montanez, Robb Report, 14 Oct. 2025

Angelica had been reading up on the struggles of the Federalists, especially her brother-in-law Alexander Hamilton’s, to ratify their blueprint for the nation. —Jane Kamensky, The Atlantic, 10 Oct. 2025

During that conversation, her brother-in-law expressed his frustration over not being invited. —Ashley Vega, PEOPLE, 10 Oct. 2025

On the witness stand, Vasquez’s brother-in-law, Luis Zuniga, remembered how eager Vasquez was to drive Zuniga’s new Ford Explorer in 2018 because officers drive the same vehicle. —Pj Green october 9, Kansas City Star, 9 Oct. 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