eighteenth
Americanadjective
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next after the seventeenth; being the ordinal number for 18.
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being one of 18 equal parts.
noun
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an eighteenth part, especially of one (1/18).
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the eighteenth member of a series.
adjective
noun
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one of 18 approximately equal parts of something
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( as modifier )
an eighteenth part
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the fraction that is equal to one divided by 18 ( 1/ 18 )
Other Word Forms
Noun Inflected Forms
Etymology
Origin of eighteenth
before 900; Middle English eightenthe, eightethe, Old English eahtatēotha. See eighteen + -th 2
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
The Dow Jones Industrial Average reached 48,500 points, marking its eighteenth record high of the year, reflecting market optimism.
From Barron's ● Dec. 11, 2025
And maybe I have piqued your interest to learn more about our most rambunctious and raucous festival season that dates back to the eighteenth century.
From Salon ● Feb. 13, 2024
The scrolls were discovered in the eighteenth century, when workmen came across the remains of a luxury villa that might have belonged to the family of Julius Caesar’s father-in-law.
From Scientific American ● Oct. 17, 2023
UBS is the eighteenth firm to reach a settlement in the US over its role in the 2008 crisis, prosecutors said.
From BBC ● Aug. 14, 2023
The wheels on his board were new, a “just because” gift from his eighteenth set of foster parents.
From "Far from the Tree" by Robin Benway
As William II himself puts it, this day, like all the "eighteenths" that went before it, has its special significance.
From The Schemes of the Kaiser by Adam, Juliette
The faces of the volutes must recede from the edge of the abacus inwards by one and a half eighteenths of that same amount.
From The Ten Books on Architecture by Vitruvius Pollio
"There aren't two eighteenths of October in one year."
From A Sheaf of Corn by Mann, Mary E.
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
