ENGLISH
REFERENCE

eighteen

num. · n.
US //ˈeɪˈtin// UK //eɪtˈiːn// eigh·teen
  1. 1 the number 18 (num.)
    A1 Beginner

    the number 18.

    the cardinal number occurring after seventeen and before nineteen.

    Example

    There are eighteen students in my English class this morning.

    Example

    The research team interviewed eighteen participants over the course of the weekend to ensure a diverse range of perspectives.

  2. 2 the age of adulthood (n.)
    B1 Intermediate

    the age when a person is legally considered an adult in many countries.

    the age of legal majority in many jurisdictions, often associated with the right to vote or purchase alcohol.

    Example

    You can apply for a driving license once you turn eighteen.

    Example

    Upon reaching the age of eighteen, citizens are granted full legal responsibilities and the right to participate in national elections.
Origin

From Middle English eightetene, eiȝtene, ehtetene, from Old English eahtatīene, eahtatēne, from Proto-Germanic *ahtōutehun. Cognate with West Frisian achttjin, Dutch achttien, German achtzehn, Danish atten. Equivalent to eight + -teen

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

Word family

Last updated June 20, 2026