eighteen

noun

1. a cardinal number, ten plus eight.
2. a symbol for this number, as 18 or XVIII.
3. a set of this many persons or things.

adjective

4. amounting to 18 in number.

noun

1. the cardinal number that is the sum of ten and eight and the product of two and nineSee also number (def. 1)
2. a numeral, 18, XVIII, etc, representing this number
3. the amount or quantity that is eight more than ten
4. something represented by, representing, or consisting of 18 units
5. (functioning as singular or plural) a team of 18 players in Australian Rules football

determiner

6. 1. amounting to eighteeneighteen weeks
   2. (as pronoun)eighteen of them knew

n.

late 14c., eightene, earlier ahtene (c.1200), from Old English eahtatene, eahtatyne; see eight + -teen. Cf. Old Saxon ahtotian, Dutch achttien, Old High German ahtozehan, German achtzehn, Old Norse attjan, Swedish adertån.