Definition of sex in US English:



  • 1(chiefly with reference to people) sexual activity, including specifically sexual intercourse.

    ‘they enjoyed talking about sex’
    ‘I didn't want to have sex with him’
    • ‘The staff can be extremely helpful, providing lots of explicit sex education without a trace of shame.’
    • ‘Janet Charlton said Daniel O'Brien frequently spoke to her about group sex during their sexual activities together.’
    • ‘Vaccination is recommended for sexually active men who have sex with men.’
    • ‘On the flip side, do we consider women who have sex with under-age boys to be paedophiles as well?’
    • ‘It's the married person's job not to cheat, not other people's duty to refuse to have sex with them.’
    • ‘In studies from the United Kingdom, the incidence and prevalence are lower in women who have sex with women than heterosexual women, but they are still at risk.’
    • ‘These early ideas have had a powerful influence on our views of sex and sexuality.’
    • ‘In fact, there have been times when I wanted to have sex with guys, but they didn't want to.’
    • ‘So I can understand the temptation to put all our resources into preventing HIV among men who have sex with men.’
    • ‘Often couples find themselves with emotional intimacy but gradually diminishing sex lives or no sex at all.’
    • ‘While men have sex with men everywhere, how people perceive that varies widely.’
    • ‘I think she's curious herself - curious about love and sex and sexuality.’
    • ‘Of course many are of the opinion that better sex education should be taught in schools.’
    • ‘Not enough of sex education in schools is focused on what happens if you do get pregnant.’
    • ‘Finally, it would be ideal to wait to have sex with that one person you are married to for life.’
    • ‘If you want to have sex with your ex just because you feel guilty, reconsider your intentions.’
    • ‘It is important to find a man who's good in bed and who loves to have sex with you.’
    • ‘She did not wish to have sex with him and did not consent to sexual intercourse.’
    • ‘He's a few years older than me, so right off the bat I told him I am not going to have sex with him, and I'm not.’
    • ‘He may be getting turned on watching them, but it's you he wants to have sex with.’
    sexual intercourse, intercourse, lovemaking, making love, sex act, sexual relations, anal penetration, sexual penetration, vaginal penetration
    the facts of life, sexual reproduction, reproduction
    have sexual intercourse, have sexual intercourse with, make love, make love to, sleep together, sleep with, go to bed together, go to bed with
    View synonyms
    1. 1.1euphemistic in singular A person's genitals.
  • 2Either of the two main categories (male and female) into which humans and most other living things are divided on the basis of their reproductive functions.

    ‘adults of both sexes’
    • ‘The two great sexes of male and female, says Milton, animate the world.’
    • ‘There has also been a growing recognition that the biological differences between the sexes extend beyond the reproductive.’
    • ‘The male and female sexes grew out of this advantage over the subsequent millions of years of evolution.’
    • ‘A work striking in its simplicity, Yoni Smile is likely a nod to the Hindu symbol for the female sex.’
    • ‘They are followed by adult males, anestrous females and immature whales of both sexes.’
    • ‘While there are only two sexes - male and female - there can be an unlimited number of genders.’
    • ‘For the purpose of this statute, it is understood that the term gender refers to the two sexes, male and female, within the context of society.’
    • ‘The difference between the sexes remains the main reason for male preference for women in their teens and twenties.’
    • ‘I wonder whether this is part of the reason that the belief that there are two and only two human sexes persists?’
    1. 2.1 The members of either sex considered as a group.
      ‘she was well known for her efforts to improve the social condition of her sex’
      • ‘Perhaps the first division of labor between the sexes was that the male became the hunter and the female the food-gatherer.’
      • ‘It's a brilliant ode that can be appreciated by members of both sexes.’
      • ‘In most species, females are the choosier sex and discriminate between several males before they choose a mate.’
      • ‘But not all members of her sex empathise with Mary, says Fergusson.’
      • ‘He was a lovelorn twit, always chasing after some impossible girl, with more need for than understanding of the female sex.’
      • ‘Originally, people believed that morality also resided with the male sex.’
      • ‘She pointed out to them that the class was unfairly divided between the sexes and that the situation would soon change.’
      • ‘I used to regard the male sex with deep suspicion - but the more my son teaches me about men, the more I like them.’
      • ‘That guy has no consideration or respect for the female sex.’
      • ‘They do so also because they believe that spending time alone with members of their own sex enriches their lives.’
      • ‘For the first time in the history of the human colony, the sexes had been segregated.’
      • ‘She then asks men to observe all of nature and find another example of how the female sex is treated the same way.’
      • ‘Shame on these women who don't use their power to help the weaker members of their sex.’
      • ‘But the attempts to rally the male sex under an equality banner were immediately cut down by the Government.’
      • ‘Elsewhere on the record, Merchant plays the role of experienced woman, dispensing advice to younger members of her sex.’
      • ‘Members of both sexes are getting heavily into debt to pay for operations on credit cards or through bank loans.’
      • ‘Is the audience for ‘Harry Potter’ divided evenly among the sexes or is it more boy-oriented?’
      • ‘Feminists might be surprised to hear it, but females are the dominant sex in most primate communities.’
      • ‘I fail to see how this is incompatible with a 35 hour week and with the capabilities of the female sex.’
      • ‘Watch them when they are talking to members of their own sex and you'll see what I mean.’
    2. 2.2 The fact of belonging to either the male or female sex.
      ‘the same allowances for childcare should be available to all single parents irrespective of sex’
      ‘the fish were separated by sex and held in storage tanks’
      • ‘It has nothing to do with the sex of a living creature.’
      • ‘A review of the literature on identifying sex from facial appearances yielded one small study from Nashville, Tennessee.’
      • ‘Kelly Holmes has been out of the army for six years now but still she bemoans the fact that her sex precluded her from getting into the boxing ring and pummelling a few people.’
      • ‘The penchant for short-term mating also showed effects of identity status and sex.’
      • ‘There are rare cases where the true sex of a child is confused because of poorly developed genital organs at birth.’
      • ‘Female sex was not a risk factor for any outcomes.’
      • ‘When people judge the group on the basis of our sex, they're missing the point.’
      • ‘Therefore, most patients in this group were selected based on their female sex.’
      • ‘They already have sons, Tristan and Angus, at the village school, and know the sex of their new baby, but are keeping the knowledge to themselves.’
      • ‘The Government is considering whether to change the law to ensure the ban on couples choosing the sex of their baby can be effectively enforced.’
      • ‘Female sex and young age are independently associated with a favourable outcome.’
      • ‘Unless there is a risk of a baby being born with a sex-linked condition such as haemophilia, therefore, she is against being able to choose the sex of your child.’
      • ‘Some attributed likeability to characteristics such as sex or nationality.’
      • ‘Despite some close friends, no one knew her true sex, and that fact was what had saved her from her mother's fate.’
      • ‘Mr Thompson claimed the dress code discriminated against him because of his sex and breached his human rights.’
      • ‘Why the sex of the donor affects the outcome of organ transplants is not known.’
      • ‘It was this direct discrimination against women, on the basis of their sex, that Emmeline Pankhurst fought to end.’
      • ‘It is virtually impossible to tell the sex of the birds, but it is statistically unlikely all eight are of the same gender, so the centre is very optimistic over breeding!’
      • ‘But it is precisely because the sex of a human is so intrinsic to their being that it should not be left to the whim of parental desire.’
      • ‘As an educated woman, Addams was constrained by the fact of her sex, and yet eager to be effective in the world.’


[with object]
  • 1Determine the sex of.

    ‘sexing chickens’
    • ‘We aged and sexed all birds captured and marked individuals with one aluminum federal band and a unique combination of three color bands.’
    • ‘Offspring were sexed at emergence and maintained in single-sex cultures.’
    • ‘We collected pupae and sexed them by the morphology of the eighth abdominal segment.’
    • ‘Animals could be sexed 1 year from birth using our enhanced feeding protocols.’
    • ‘I think they came over because they were more adept at sexing chickens than we were.’
  • 2sex something upinformal Present something in a more interesting or lively way.

    ‘the department set up a task force to help sex up the concept of conserving water’
    • ‘As a result, ordinary academic books have been sexed up by mainstream publishers and heavily promoted in the mass market.’
    • ‘‘The dossier was not sexed up by him or anyone else,’ said the committee.’
    • ‘In his historical pastiche, Wells elects to take the past and sex it up a little.’
    • ‘Apparently, they accused the Government of sexing things up.’
    • ‘Six days later He gave evidence and said it was untrue the dossier had been sexed up or that the government had pressured intelligence agencies.’
    • ‘Gilligan had a genuine scoop - but made the mistake of sexing it up a notch too far.’
    • ‘His first couple of books were mysteries, and she said she liked them well enough, but by the time he started his third novel he was agitated about the lackluster sales, so he tried sexing things up.’
    • ‘They have really gone out of their way to sex this series up.’
    • ‘There is little attempt to sex things up for a restless modern audience or indulge in self-conscious irony.’
    • ‘‘There's a danger of treating the election as if it's boring so that you have to sex it up,’ he said, at today's official launch of the BBC's election night coverage.’
  • 3sex someone upinformal Arouse or attempt to arouse someone sexually.

    • ‘I can easily sleep with him, not sex him up, but just sleep, peacefully, in the same bed.’


On the difference in use between the words sex (in sense 2 above) and gender, see gender


Late Middle English (denoting the two categories, male and female): from Old French sexe or Latin sexus.