sister-in-law

noun

sis·​ter-in-law ˈsi-st(ə-)rən-ˌlȯ 

-tərn-ˌlȯ

plural sisters-in-law ˈsi-stər-zən-ˌlȯ 

1

: the sister of one's spouse

2

a

: the wife of one's sibling

b

: the wife of one's spouse's sibling

Examples of sister-in-law in a Sentence

Recent Examples on the Web

Lee Chun Ho, 40, his father, Simon Lee, 70, and his sister-in-law, Esther Chan, 38. — New York Times, 20 July 2026

Bay Area News Group reported that John Boisa identified the two women as his sister and sister-in-law. — Sacbee.com, 17 July 2026

John Boisa identified the other two people still missing as his sister, Carol Boisa, as well his sister-in-law — and Clifford Boisa’s wife — Jackie Boisa. — Jakob Rodgers, Mercury News, 17 July 2026

The statement came from Sky and Amanda Roberts, Roberts Giuffre’s brother and sister-in-law, who have become some of the lead spokespeople of Epstein accusers since Roberts Giuffre died by suicide in 2025. — Erin Mansfield, USA Today, 16 July 2026

Word History

First Known Use

15th century, in the meaning defined at sense 1

Rhymes for sister-in-law

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

Kids Definition

sister-in-law

noun

sis·​ter-in-law

ˈsis-t(ə-)rən-ˌlȯ, 

-tərn-ˌlȯ

plural sisters-in-law

-tər-zən-

1

: the sister of one's spouse

2

a

: the wife of one's sibling

b

: the wife of one's spouse's sibling