EIGHTEENTH definition: next after the seventeenth; being the ordinal number for 18. See examples of eighteenth used in a sentence.

(Definition of eighteenth from the Cambridge Advanced Learner's Dictionary & Thesaurus © Cambridge University Press)

Nov 27, 2025 · eighteenth (plural eighteenths) The person or thing in the eighteenth position. One of eighteen equal parts of a whole. (informal) A party to celebrate an eighteenth birthday.

eighteenth (ˈeɪˈtiːnθ) adj (Mathematics) (usually prenominal) a. coming after the seventeenth in numbering or counting order, position, time, etc; being the ordinal number of eighteen: often written 18th

The meaning of EIGHTEENTH is being number 18 in a countable series. How to use eighteenth in a sentence.

Definition of eighteenth noun in Oxford Advanced Learner's Dictionary. Meaning, pronunciation, picture, example sentences, grammar, usage notes, synonyms and more.

WordReference Random House Unabridged Dictionary of American English © 2024 eight•eenth (ā′ tēnth′), adj. next after the seventeenth; being the ordinal number for 18. being one of 18 equal parts. …

Eighteenth definition: The ordinal number matching the number 18 in a series.

The eighteenth item in a series is the one that you count as number eighteen. The talks are now in their eighteenth day.

eighteenth Other forms: eighteenthly; eighteenths Definitions of eighteenth adjective coming next after the seventeenth in position synonyms: 18th