Definition of adult in English:

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Pronunciation: /əˈdəlt/
Pronunciation: /ˈadˌəlt/


1A person who is fully grown or developed: children should be accompanied by an adult
More example sentences
  • The years passed as the children grew into adults, left home and came home again when on holidays.
  • It's about two youths and the evolution of their relationship as they grow into adults.
  • How can something so small require the undivided attention of two grown adults and still not be satisfied?
1.1A fully developed animal.
Example sentences
  • John White invented a device, using a laser, to knock out just one cell in a worm, either in a developing animal or an adult.
  • The latter possibility is very unlikely, as the animal was an adult.
  • The four adult and two baby animals will travel down from their home in the Cairngorm mountains of Scotland to pull the sledge, laden with toys, around town.
1.2 Law A person who has reached the age of majority. See majority (sense 2).
Example sentences
  • It also discussed the current position, whereby the consent of an adult with parental responsibility will be valid even when the child is able to give a valid consent but refuses to do so.
  • Were he an adult with a criminal record, it is almost certain he would face a significant period of imprisonment.
  • The Appellant is now a young adult of 20 years of age.


1(Of a person or animal) fully grown or developed: the adult inhabitants of the U.S.
More example sentences
  • It is assumed, in these contexts, that normal, fully developed adult human beings are responsible beings.
  • Most animals are developmentally programmed to grow to a characteristic adult size.
  • In the 10 years since then, children's fare has grown more sophisticated and adult expectations have diminished, creating a space in the middle where they can all meet.
mature, grown-up, fully grown, full-grown, fully developed, of age, of legal age
1.1Of or for adult people: adult education the responsibilities of adult life
More example sentences
  • With no education or adult help, this is a daunting task.
  • The children will devise, plan and implement a programme to get adult relatives back into education.
  • Teenage mothers often face daunting obstacles to completing their education and achieving adult independence.
1.2Emotionally and mentally mature: an effort to be adult and civilized
More example sentences
  • ‘He is determined to turn his life around and deal with matters in a more responsible, mature and adult way,’ Mr Jones said.
  • And he should be adult enough and mature enough and experienced enough to understand it.
  • Mature, adult comprehension can lead us all to see that there are some very intelligent and worthy of praise men out there.
1.3Sexually explicit or pornographic (used euphemistically to refer to a movie, book, or magazine).
Example sentences
  • It turned out the lawyers were referring to dozens of adult magazines seized from his home.
  • We also assessed the availability of products that could be used as educational or therapeutic products, such as adult magazines, books, and videos.
  • Dietz and Sears examined books, magazines, and films in adult bookstores in four cities.
sexually explicit, pornographic, obscene, smutty, dirty, rude, erotic, sexy, suggestive, titillating;
porn, porno, naughty, blue, X-rated


Mid 16th century: from Latin adultus, past participle of adolescere 'grow to maturity' (see adolescent).

  • adolescent from Late Middle English:

    Both adolescent and adult (mid 16th century) come from Latin adolescere, ‘to grow to maturity’. The root of the Latin word is alescere ‘to grow up’, which in turn derives from alere ‘to nourish or give food to’, so the idea of coming to maturity is closely related to the idea of feeding yourself up. See also alimony

For editors and proofreaders

Syllabification: a·dult

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