[uh-duhlt, ad-uhlt]
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  1. having attained full size and strength; grown up; mature: an adult person, animal, or plant.
  2. of, relating to, or befitting adults.
  3. intended for adults; not suitable for children: adult entertainment.
  1. a person who is fully grown or developed or of age.
  2. a full-grown animal or plant.
  3. a person who has attained the age of maturity as specified by law.

Origin of adult

1525–35; 1925–30 for def 3; < Latin adultus grown (past participle of adolēre to make grow), equivalent to ad- ad- + ul- (identical with base al- in aliment, ol- in prolific) + -tus past participle suffix
Related formsa·dult·hood, nouna·dult·like, adjectivea·dult·ly, adverba·dult·ness, nounnon·a·dult, adjective, nounqua·si-a·dult, adjectivesub·a·dult, adjective, nounsub·a·dult·ness, nounun·a·dult, adjective Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for adult

Contemporary Examples of adult

Historical Examples of adult

British Dictionary definitions for adult


  1. having reached maturity; fully developed
  2. of or intended for mature peopleadult education
  3. regarded as suitable only for adults, because of being pornographicadult films and magazines
  1. a person who has attained maturity; a grownup
  2. a mature fully grown animal or plant
  3. law a person who has attained the age of legal majority (18 years for most purposes)Compare infant
Derived Formsadulthood, noun

Word Origin for adult

C16: from Latin adultus, from adolēscere to grow up, from alēscere to grow, from alēre to feed, nourish
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for adult

1530s (but not common until mid-17c.), from Latin adultus "grown up, mature, adult, ripe," past participle of adolescere "grow up, mature" (see adolescent). As a euphemism for "pornographic," it dates to 1958 and does no honor to the word.


"adult person," 1650s, from adult (adj.).

Online Etymology Dictionary, © 2010 Douglas Harper

adult in Medicine


[ə-dŭlt, ădŭlt]
  1. One who has attained maturity or legal age.
  2. A fully grown, mature organism.
  1. Fully developed and mature.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.