adult

noun

: one that is adult

especially : a human being after an age (such as 21) specified by law

adultlike

ə-ˈdəlt-ˌlīk 

adjective

Synonyms of adult

• grown-up
• elder

Examples of adult in a Sentence

Her books appeal both to children and to adults.

Children must be accompanied by an adult in the museum.

Only adults can purchase alcohol.

This film is for adults only. Minors are not admitted.

People who are close friends as children aren't always friends as adults.

studying interactions between young birds and adults

Recent Examples on the Web

Police found that two adult men had been involved in an altercation when one of the men struck the other multiple times, authorities said. —Caelyn Pender, Mercury News, 10 June 2026

It can’t really even be argued that this is a game unfolding between two adults. —Literary Hub, 10 June 2026

According to the research available, valerian is suggested to be generally safe for short-term use (up to six weeks) by most adults in doses of 300 to 600 milligrams daily. —Heather Jones, Verywell Health, 9 June 2026

General admission prices for adults start at $17, if purchased in advance. —Ut Community Press, San Diego Union-Tribune, 9 June 2026

Word History

Etymology

derivative of adult entry 1

First Known Use

1655, in the meaning defined above

Phrases Containing adult

• adult alternative
• adult education
• adult life
• adult-onset diabetes
• adult respiratory distress syndrome
• consenting adult
• pre-adult
• young adult

Rhymes for adult

• consult
• exult
• insult
• occult
• result
• catapult
• subadult
• cult

Kids Definition

adult

1 of 2 adjective

ə-ˈdəlt  ˈad-ˌəlt 

1

: fully developed and mature

2

: of, relating to, or characteristic of adults

adulthood

ə-ˈdəlt-ˌhu̇d 

noun

adultness

ə-ˈdəlt-nəs 

ˈad-ˌəlt-

noun

adult

2 of 2 noun

: a fully grown person, animal, or plant

adultlike

ə-ˈdəlt-ˌlīk 

adjective

Etymology

from Latin adultus "having grown up," from adolescere "to grow up" — related to adolescence

Medical Definition

adult

1 of 2 adjective

ə-ˈdəlt  ˈad-ˌəlt 

: fully developed and mature

adult

2 of 2 noun

1

: one that has arrived at full development or maturity especially in size, strength, or intellectual capacity

2

: a human male or female after a specific age (as 18 or 21)

Legal Definition

adult

noun

: a person who has reached an age specified by law compare child, infant, minor