\ˈseks \

Definition of sex 

(Entry 1 of 2)

1 : either of the two major forms of individuals that occur in many species and that are distinguished respectively as female or male especially on the basis of their reproductive organs and structures

2 : the sum of the structural, functional, and behavioral characteristics of organisms that are involved in reproduction marked by the union of gametes and that distinguish males and females

3a : sexually motivated phenomena or behavior

b : sexual intercourse

4 : genitalia


sexed; sexing; sexes

Definition of sex (Entry 2 of 2)

transitive verb

1 : to identify the sex of sex newborn chicks

2a : to increase the sexual appeal of often used with up

b : to arouse the sexual desires of

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Examples of sex in a Sentence


The form asks for your name, age, and sex. The couple didn't know what the sex of their baby would be. How do you tell the sex of a hamster? discrimination on the basis of sex Some feel men are the more aggressive sex. All he ever thinks about is sex. Her mom talked to her about sex. She doesn't like all the sex and violence in movies. He had sex with his girlfriend.
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Recent Examples on the Web: Noun

While UTIs affect people of all sexes and ages, Kathleen Kobashi, a urologist at Virginia Mason Medical Center in Seattle, tells Allure that women are much more likely to be afflicted thanks to their anatomy. Carolyn Todd, Allure, "This Is Why You Keep Getting UTIs After Sex," 13 Aug. 2018 Men Are From Mars, Women Are From Venus was the wildly popular self-help book from the 1990s that predicated marital success on understanding the fundamental differences between the sexes. Anne Roderique-jones, SELF, "I Tested ‘Love Languages’ and 3 Other Relationship Books on My Marriage," 7 Oct. 2018 The controversy erupting around the Kavanaugh nomination underlines the power of the #MeToo movement, which is predicated on the idea that the dynamics between the sexes rob women of their power. Libby Locke, WSJ, "The Attack on Kavanaugh Is Un-American," 26 Sep. 2018 The practice is so widespread across both sexes that addressing it on a case-by-case basis — instead of as a public health problem — may be insufficient, the researchers said. Emily Baumgaertner, New York Times, "How Many Teenage Girls Deliberately Harm Themselves? Nearly 1 in 4, Survey Finds.," 2 July 2018 But there remains a long way to go until the sexes are equally represented in Congress. David Johnson, Time, "This Map Shows When Each State First Elected a Woman to Congress," 26 June 2018 The most common source of financial education for both sexes came from members of their immediate families. Adam Shell, USA TODAY, "401(k) investing: How Millennial men and women invest differently," 12 June 2018 And 73% of American Jews but only 42% of Israeli Jews support both sexes praying together at the Western Wall rather than the strict separation required by Orthodox Judaism. William A. Galston, WSJ, "The Fracturing of the Jewish People," 12 June 2018 There may be a battle of the sexes about movies on Facebook, but not in our house. Lisa Cianci,, "'The Book Club': My husband saw a chick flick with me; should he give up his 'man card?'," 29 May 2018

Recent Examples on the Web: Verb

Yandy’s ark of offerings is evidence that pretty much any animal can be sexed up, although not all animals are equally alluring. Rachel Sugar, Vox, "Why are “sexy” cats a thing?," 26 Oct. 2018 The most sexed-up take on the look saw one guy swaggering down the runway like a cheeky gunslinger. Liana Satenstein, Vogue, "Are You Ready for the Return of Tighty-Whities? Gucci Sure Is," 25 Sep. 2018 Wills is officially headed to paradise, or, at least, sexed-up Bachelor Nation spin-off series Bachelor In Paradise, as People announced., "Can We Start The Wills Reid For Bachelor Campaign Right Now?," 10 July 2018 The classic look would often get sexed up with spit curls that lay slicked to the forehead, at the nape of the neck, or in front of the ear, thanks to the influence of Josephine Baker. Rebecca Norris, Allure, "Watch 100 Years of Iconic Short-Hair Trends in Under Four Minutes," 22 May 2018 Each walleye harvested by the tribes is measured and sexed. Paul A. Smith, Milwaukee Journal Sentinel, "Smith: Researchers document walleye decline in Wisconsin waters," 9 May 2018 What ensues is a modern-day, faintly unpleasant, sexed-up comedy of errors on both sides. Jocelyn Mcclurg, USA TODAY, "Curtis Sittenfeld has her finger on America's pulse in 10 witty, zippy short stories," 30 Apr. 2018 His aura was a regal, ethereal, sexed-up shade of purple, and his style had to match all of that pomp. Brooke Bobb, Vogue, "Meet the Man Who Made 3,000 Pairs of High Heels for Prince," 19 Apr. 2018 Because the star of the show, one Jean-Paul Belmondo, just totally sexes up the screen. Maura Kelly, Marie Claire, "The 10 Hottest International Male Movie Stars Evvv-ah," 28 May 2010

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

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First Known Use of sex


14th century, in the meaning defined at sense 1


1878, in the meaning defined at sense 1

History and Etymology for sex


Middle English, from Latin sexus

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Learn More about sex

Dictionary Entries near sex



sew up


sex act



Statistics for sex

Last Updated

7 Dec 2018

Look-up Popularity

Time Traveler for sex

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

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More Definitions for sex



English Language Learners Definition of sex

: the state of being male or female

: men or male animals as a group or women or female animals as a group

: physical activity in which people touch each other's bodies, kiss each other, etc. : physical activity that is related to and often includes sexual intercourse


\ˈseks \

Kids Definition of sex

1 : either of two divisions into which many living things can be divided according to their roles in reproduction and which consist of males or females

2 : the state of being male or female The form asks for your name, age, and sex.

3 : sexual activity


\ˈseks \

Medical Definition of sex 

(Entry 1 of 2)

1 : either of the two major forms of individuals that occur in many species and that are distinguished respectively as male or female

2 : the sum of the structural, functional, and behavioral characteristics of living things that are involved in reproduction by two interacting parents and that distinguish males and females

3a : sexually motivated phenomena or behavior

b : sexual intercourse

Medical Definition of sex (Entry 2 of 2)

: to identify the sex of techniques for sexing human embryos

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More from Merriam-Webster on sex

Rhyming Dictionary: Words that rhyme with sex

Thesaurus: All synonyms and antonyms for sex

Spanish Central: Translation of sex Encyclopedia article about sex

Comments on sex

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


to enclose within walls

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