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

His sister-in-law also spoke on behalf of the Beam family. —Andrea Nakano, CBS News, 10 Dec. 2025

That’s my sister, not my sister-in-law. —Ashley Hume, FOXNews.com, 8 Dec. 2025

Kelleher’s involvement became even more personal when her sister-in-law, confronted five years ago with the return of her breast cancer, turned to Cancer and Careers. —Noor Lobad, Footwear News, 5 Dec. 2025

The new film tracks the romantic entanglements of a now 50-something Barry McMullen (Burns) and his 20-something kids, as well as his brother Patrick (Michael McGlone) and widowed sister-in-law Molly (Connie Britton), each facing unexpected romantic hurdles of their own. —Jessica Radloff, Glamour, 30 Nov. 2025

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