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Definitions

sister-in-law

[sis-ter-in-law] / ˈsɪs tər ɪnˌlɔ /
NOUN
kinsman
Synonyms
STRONG
agnate aunt blood brother-in-law cognate connection cousin father father-in-law folk folks grandparents in-laws kin kinsperson kinswoman mother mother-in-law nephew niece relation sib sibling stepbrother stepparent stepsister uncle
WEAK
clansperson great-grandparents
NOUN
kinswoman
Synonyms
STRONG
agnate aunt blood brother-in-law cognate connection cousin father father-in-law folk folks grandparents in-laws kin kinsman kinsperson mother mother-in-law nephew niece relation sib sibling stepbrother stepparent stepsister uncle
WEAK
clansperson great-grandparents
NOUN
relative
Synonyms
STRONGEST
aunt cousin father folk mother niece sibling uncle
STRONG
agnate blood brother-in-law cognate connection father-in-law folks grandparents in-laws kinsperson mother-in-law nephew relation sib stepbrother stepparent stepsister
WEAK
clansperson great-grandparents

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

The employee was his sister-in-law, the person confirmed.

From Los Angeles Times • Feb. 18, 2026

However, detective work by his sister-in-law tracked down a social media profile for Patrick Hanna.

From BBC • Feb. 17, 2026

My sister-in-law Eva Rose, who also lives nearby and also came to the intersection separately, described to me the moment the agents’ anger was unleashed a second time as she arrived 15 minutes later.

From Slate • Jan. 25, 2026

Charlie Pasarell, a tennis player who was one of ProServ’s early clients, introduced his sister-in-law, Marcee Fareed, to Craighill in 1978.

From The Wall Street Journal • Jan. 21, 2026

“This is my niece, Robin. When my brother and sister-in-law died, I took her in.”

From "Dragonwings" by Laurence Yep

From Roget's 21st Century Thesaurus, Third Edition Copyright © 2013 by the Philip Lief Group.