\ˈtwin \

Definition of twin 

(Entry 1 of 3)

1a : either of two offspring produced at a birth

b Twins plural : gemini

2 : one of two persons or things closely related to or resembling each other

3 : a compound crystal composed of two adjoining crystals or parts of crystals of the same kind that share a common plane of atoms



Definition of twin (Entry 2 of 3)

1 : born with one other or as a pair at one birth my twin brother twin girls

2a : made up of two similar, related, or connected members or parts : double

b : paired in a close or necessary relationship : matching

c : having or consisting of two identical units

d : being one of a pair


twinned; twinning

Definition of twin (Entry 3 of 3)

transitive verb

1 : to bring together in close association : couple

intransitive verb

1 : to bring forth twins

2 of a crystal : to grow in a compound form with two adjoining sections that share a common plane of atoms

Keep scrolling for more

Other Words from twin


twinship \ˈtwin-​ˌship \ noun

Synonyms & Antonyms for twin

Synonyms: Noun

companion, fellow, half, match, mate

Synonyms: Adjective

binary, bipartite, double, double-barreled, double-edged, dual, duplex, twofold

Antonyms: Adjective


Visit the Thesaurus for More 

Examples of twin in a Sentence


She's the mother of twins. The twins went swimming after lunch. My sister just had twins. Sarah and her brother are twins.


the twin goals of reducing oil dependence and protecting the environment
See More

Recent Examples on the Web: Noun

In the case of one of the twins born, the deletion eliminates 15 base pairs, meaning the CCR5 protein will lack five amino acids but otherwise be normal. John Timmer, Ars Technica, "Scientists, ethicists slam decisions behind gene-edited twins," 30 Nov. 2018 Running for Legislator for Maine's District 134 Genevieve McDonald, running for the Maine House of Representatives, would be the first new mother of twins to serve in the Maine legislature. Jill Filipovic, Harper's BAZAAR, "Your State-by-State Guide to Women Running in the Midterms," 31 Oct. 2018 Another set of twins, Yekaterina and Alexandra Nemich, collected bronze for Kazakhstan. John Pye, The Seattle Times, "Christie wins host Indonesia’s signature gold at Asian Games," 28 Aug. 2018 Beyoncé gave birth to her and Jay-Z's first daughter, Blue Ivy, in 2012 and welcomed twins Rumi and Sir in June 2017. Rachel Epstein, Marie Claire, "Beyoncé on How She Learned to Love Her Body After Giving Birth," 6 Aug. 2018 Those columns were written by a pair of twins whose parents named them Esther Pauline and Pauline Esther, which establishes off the bat that good judgment isn’t hereditary. New York Times, "Wisdom Dispensed With Slaps and Puns: A Sprightly History of Advice-Giving," 1 June 2018 Of course, Twitter went wild seeing their favorite twins in a brotherly feud. Carolyn Twersky, Seventeen, "Cole and Dylan Sprouse Are Trolling Each Other On Twitter and It's Funny AF," 20 July 2018 The newfound planet and its apparent twin were both discovered by direct imaging, a tricky method that has, until now, identified only very distinctive worlds. Meghan Bartels,, "Twin Exoplanets Look Alike, Act Alike … But Have Completely Different Origins," 18 July 2018 Holly Brooks is a two-time Olympic skier and two-time Mount Marathon winner who lives in Anchorage with her husband, Rob, and their twins. Holly Brooks, Anchorage Daily News, "It’s gonna be a hot Mount Marathon, so racers be warned and spectators stand by — preferably with ice," 3 July 2018

Recent Examples on the Web: Adjective

The tunnel and new pipeline segment will replace twin pipelines now resting on the bottom of the straits. John Flesher, The Seattle Times, "Michigan governor signs bill allowing Great Lakes oil tunnel," 12 Dec. 2018 Printy Pets blankets come in three sizes: puppy size, twin/full size, and queen/king size. Brittney Morgan, House Beautiful, "These Custom Blankets Exist So You Can Always Cuddle With Your Pet—And, They’re On Sale Now," 6 Dec. 2018 During last week's InSight landing, the Mars Recon Orbiter and Odyssey both served as communication relays (along with two twin CubeSats that launched with InSight earlier this year). Joe Pappalardo, Popular Mechanics, "What Human Beings Can Teach Aliens About Probing the Solar System," 5 Dec. 2018 Choose between five colors and four sizes — throw, twin, queen, and king. Rachel Rothman, Good Housekeeping, "The 5 Best Electric Blankets to Keep You Warm and Cozy All Night Long," 29 Nov. 2018 Once its twin circular solar panels open, the lander will occupy the space of a large car. Marcia Dunn, The Seattle Times, "Mars revisited: NASA spacecraft days away from risky landing," 21 Nov. 2018 The oldest and youngest were twin zebras; Dorothy and the Tin Man; a ladybug and a bumblebee. Elisabeth Egan, Glamour, "I Always Take My Kids Trick-or-Treating. This Year I Was Fired.," 29 Oct. 2018 It was revealed that Sabrina's twin Katrina was actually the evil one, a discovery made after Katrina attempted to throw Sabrina into a volcano. Jessica Macleish, Teen Vogue, "11 Differences Between "Chilling Adventures of Sabrina" and "Sabrina the Teenage Witch"," 26 Oct. 2018 And just as fun and cleverly off-kilter were the styles, from a flamingo-hued half-up look remixed with twin raver knots to a hyper-bleached pixie accented with a single fuchsia micro braid trailing down the back like an ethereal rattail. Lauren Valenti, Vogue, "Eye-Popping Hair Rules the Street at Tokyo Fashion Week," 19 Oct. 2018

Recent Examples on the Web: Verb

This is hardly the first time Kate has twinned with Princess Di. Erica Gonzales, Harper's BAZAAR, "Kate Middleton Had a Princess Diana Moment in Her Gray Blazer," 30 Oct. 2018 Models Gigi and Anwar Hadid arrived earlier today at Milan’s Malpensa airport, just in time for the city’s Spring 2019 shows and twinned like siblings might do in patchwork trousers. Edward Barsamian, Vogue, "Gigi and Anwar Hadid Hit Milan in Matching Patchwork Pants," 19 Sep. 2018 But the series also twins that idea with the idea of blame, the idea of finding a scapegoat and sometimes even a completely justifiable scapegoat. Todd Vanderwerff, Vox, "BoJack Horseman season 5 is a bold, bracing look at a culture that shirks responsibility," 15 Sep. 2018 Getty ImagesSplash Proof Kim and Kylie are always twinning. Marina Liao, Marie Claire, "Kylie Jenner ​Morphed Into Kim Kardashian Circa 2015 in This Latex Dress​," 7 Sep. 2018 Beyoncé has twinned winningly with 6-year-old Blue Ivy in hers-and-hers Gucci denim and dresses. Michelle Ruiz, WSJ, "Mommy-and-Me Style: Cute or Creepy?," 17 July 2018 And in the latest moment in off-screen friendship goals, Camila Mendes and Madelaine Petsch were twinning in an always fashionable color combination. Lauren Rearick, Teen Vogue, "Camila Mendes and Madelaine Petsch Matched in Black and White Outfits," 15 July 2018 Lopez and Rodriguez visited his TruFusion workout studio and wore twinning shades of white, blue, and neon yellow. Edward Barsamian, Vogue, "Jennifer Lopez Takes an Hermès Kelly (and Alex Rodriguez) to the Gym," 24 May 2018 Kate Hudson‘s family vacation in Greece continues, as the actress shared a sweet shot of her son Ryder and stepdad Kurt Russell twinning on a boat on Monday. Dana Rose Falcone,, "Kate Hudson' Son Ryder, 14, Looks Just Like Grandpa Kurt Russell on Vacation in Greece," 19 June 2018

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

See More

First Known Use of twin


14th century, in the meaning defined at sense 1a


1593, in the meaning defined at sense 1


14th century, in the meaning defined at transitive sense 1

History and Etymology for twin


Middle English, from twin twofold


Middle English, twofold, double, from Old English twinn; akin to Old Norse tvinnr two by two, Old English twā two

Keep scrolling for more

Learn More about twin

Dictionary Entries near twin






twin band mill

twin bed

Statistics for twin

Last Updated

14 Dec 2018

Look-up Popularity

Time Traveler for twin

The first known use of twin was in the 14th century

See more words from the same century

Keep scrolling for more

More Definitions for twin



English Language Learners Definition of twin

 (Entry 1 of 3)

: either one of two babies that are born at the same time to the same mother

: either one of two similar things that form a pair



English Language Learners Definition of twin (Entry 2 of 3)

: to bring (two things) together in close association

: to form a relationship between (two towns in two countries)



English Language Learners Definition of twin (Entry 3 of 3)

—used to describe children who are twins

: made up of two similar things that are used together

: forming one of a pair of related or connected ideas or places


\ˈtwin \

Kids Definition of twin

 (Entry 1 of 2)

1 : either of two offspring produced at one birth

2 : one of two persons or things closely related to or very like each other On the opposite side of the river is the city's twin.



Kids Definition of twin (Entry 2 of 2)

1 : born with one other or as a pair at one birth my twin brother

2 : made up of two similar, related, or connected members or parts a twin-engine airplane

3 : being one of a pair Her face was a pasty white with twin spots of rouge on the cheeks.— Gail Carson Levine, Ella Enchanted


\ˈtwin \

Medical Definition of twin 

(Entry 1 of 2)

: born with one other or as a pair at one birth a twin brother twin girls



Medical Definition of twin (Entry 2 of 2)

1 : either of two offspring produced at a birth

2 twins plural : a group of two offspring born at one birth

Other Words from twin

twinship \-​ˌship \ noun

Keep scrolling for more

More from Merriam-Webster on twin

Rhyming Dictionary: Words that rhyme with twin

Thesaurus: All synonyms and antonyms for twin

Spanish Central: Translation of twin

Nglish: Translation of twin for Spanish Speakers

Britannica English: Translation of twin for Arabic Speakers Encyclopedia article about twin

Comments on twin

What made you want to look up twin? Please tell us where you read or heard it (including the quote, if possible).


a nest or breeding place

Get Word of the Day daily email!

Test Your Vocabulary

Late Autumn 2018 Words of the Day Quiz

  • frosted-autumn-leaves
  • Which is a synonym of yahoo?
Name That Thing

Test your visual vocabulary with our 10-question challenge!

Word Winder's CrossWinder

Test Your Knowledge - and learn some interesting things along the way.


Love words? Need even more definitions?

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