sis·​ter | \ ˈsi-stər How to pronounce sister (audio) \

Definition of sister

1 : a female who has one or both parents in common with another
2 often capitalized
a : a member of a women's religious order (as of nuns or deaconesses) especially : one of a Roman Catholic congregation under simple vows
b : a girl or woman who is a member of a Christian church
3a : a girl or woman regarded as a comrade
b : a girl or woman who shares with another a common national or racial origin especially : a Black girl or woman
4 : one that is closely similar to or associated with another sister cities
5 chiefly British : nurse
6a : girl, woman
b : person usually used in the phrase weak sister
7 : a member of a sorority

Examples of sister in a Sentence

The sisters live in the convent.
Recent Examples on the Web The Biden administration did not immediately confirm details of the prisoner swap, but a sister of Frerichs, who is from Lombard, Illinois, thanked U.S. government officials who helped secure her brother’s release. Eric Tucker, Chicago Tribune, 19 Sep. 2022 President Joe Biden met with Cherelle Griner, wife of WNBA star Brittney Griner, and the sister of former Marine Paul Whelan in the Oval Office on Friday. Paige Mcglauflin, Fortune, 19 Sep. 2022 Carol Barnes, the sister of David Barnes, said his trial is scheduled for September 21. William Thornton |, al, 16 Sep. 2022 Wantchekon posits, though, that Queen Hangbe, the twin sister of King Akaba, planted the seed for the idea of the women warriors in the early 1700s. Laura Zornosa, Time, 16 Sep. 2022 Biden sat down with Elizabeth Whelan, the sister of Paul Whelan. Eric Tucker,, 16 Sep. 2022 The Associated Press first reported the news that Biden will host Griner's camp and the sister of Paul Whelan, the Michigan corporate security executive who is also jailed in Russia. Chris Bumbaca, USA TODAY, 15 Sep. 2022 Yelena, the adoptive sister of Scarlett Johansson's Natasha Romanoff, later returned on Disney+'s Hawkeye series. Randall Colburn,, 10 Sep. 2022 She was recognized as a princess in 2020—she's the half-sister of King Philippe. Emily Burack, Town & Country, 10 Sep. 2022 See More

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'sister.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of sister

before the 12th century, in the meaning defined at sense 1

History and Etymology for sister

Middle English suster, sister, partly from Old English sweostor and partly from Old Norse systir sister; akin to Latin soror sister, Sanskrit svasṛ

Learn More About sister

Time Traveler for sister

Time Traveler

The first known use of sister was before the 12th century

See more words from the same century

Dictionary Entries Near sister



sister block

See More Nearby Entries 

Statistics for sister

Last Updated

21 Sep 2022

Cite this Entry

“Sister.” Dictionary, Merriam-Webster, Accessed 1 Oct. 2022.

Style: MLA
MLACheck Mark Icon ChicagoCheck Mark Icon APACheck Mark Icon Merriam-WebsterCheck Mark Icon

More Definitions for sister


sis·​ter | \ ˈsi-stər How to pronounce sister (audio) \

Kids Definition of sister

1 : a female person or animal related to another person or animal by having one or both parents in common
2 : a member of a religious society of women : nun
3 : a woman related to another by a common tie or interest

Other Words from sister

sisterly adjective


sis·​ter | \ ˈsis-tər How to pronounce sister (audio) \

Medical Definition of sister

chiefly British
: a head nurse in a hospital ward or clinic broadly : nurse


Test Your Vocabulary

Commonly Confused Words Quiz

  • vector image of a face with thought expression
  • I went to the ______ store to buy a birthday card.
How Strong Is Your Vocabulary?

Test your vocabulary with our 10-question quiz!

Universal Daily Crossword

A daily challenge for crossword fanatics.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!