adult

[uh-duhlt, ad-uhlt]

noun

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.

adjective

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.

verb (used without object)

1. Informal.,  (of a young person) to do things and assume responsibilities that are associated with being an adult; act like an adult (usually used facetiously about minor accomplishments).

   I cook dinner for myself most nights—guess that means I'm adulting.

adult

/ ˈædʌlt, əˈdʌlt /

adjective

1. having reached maturity; fully developed

2. of or intended for mature people

   adult education

3. regarded as suitable only for adults, because of being pornographic

   adult films and magazines

noun

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

Other Word Forms

• adulthood noun
• adultlike adjective
• adultly adverb
• adultness noun
• nonadult adjective
• quasi-adult adjective
• subadult adjective
• subadultness noun
• unadult adjective

Word History and Origins

Origin of adult¹

First recorded in 1525–35; from Latin adultus “grown” (past participle of adolēre “to make grow”), equivalent to ad- ad- + ul- (identical with base al- in aliment ( def. ) ) + -tus past participle suffix

Word History and Origins

Origin of adult¹

C16: from Latin adultus, from adolēscere to grow up, from alēscere to grow, from alēre to feed, nourish

Example Sentences

Before he can yank the branch from his truck’s wheel well, the adults are on top of him.

Read more on Salon

The federal government’s new directory that allows older adults to look up which doctors and hospitals accept their Medicare Advantage insurance contains errors, creating confusion at the start of the annual Medicare open-enrollment period.

Read more on MarketWatch

That was in keeping with guidance from the National Institute on Alcohol Abuse and Alcoholism that healthy adults over 65 partake of no more than seven drinks a week.

Read more on The Wall Street Journal

In humans, the dental lamina disintegrates after we grow our adult teeth, but many vertebrates retain the ability to replace their teeth.

Read more on Science Daily

The father of three adult children was curious about playing tight end—but he and his coach settled on defensive line.

Read more on The Wall Street Journal

Related Words

• man 
• person 
• woman 

When To Use

What does adult mean?

An adult is a person who is fully grown or developed. This could refer to a person’s body being done growing or their mind being fully developed. An adult child is someone’s child who is fully grown, as in Murray’s adult children are all married and have children of their own.An adult is also a person who has reached an age that their society says allows them responsibilities and benefits not allowed to children. For example, in the United States someone who is 18 years old is in many cases considered an adult. Eighteen-year-olds can vote, sign a contract, join the military, and other actions children are not allowed to do.An adult can also be a fully grown or matured plant or animal, as in Once my puppy becomes an adult, I’ll need to get them a bigger crate.Adult can also be used to describe something related to adults or adulthood, such as adult responsibilities—like paying rent.Adult can also be used to describe something not suitable for children. Things labeled as adult entertainment, for example, often include explicit sexual content.Informally, adult can be used as a verb meaning to take on responsibilities usually reserved for adults, such as owning a house. It’s often used humorously to describe small responsibilities, as in Tanya really adulted today by putting away her laundry.