quintillion

noun

quin·​til·​lion kwin-ˈtil-yən How to pronounce quintillion (audio)
US : a number equal to 1 followed by 18 zeros see Table of Numbers
also, British : a number equal to 1 followed by 30 zeros see Table of Numbers
quintillion adjective
quintillionth
kwin-ˈtil-yən(t)th How to pronounce quintillion (audio)
adjective or noun

Examples of quintillion in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
There, interactions between streams of liquid iron generate a magnetic field one quintillion times more powerful than that of an ordinary lab magnet (but thousands of times weaker than the Sun’s). — Literary Hub, 27 Oct. 2025 Both of these decay rapidly into even more particles, so in the end, ultrahigh-energy protons (with more than 50 quintillion eV) from distant galaxies should never reach us. — Phil Plait, Scientific American, 3 Apr. 2026 In 1946, Hungary replaced the pengö with a new currency—the forint—at a rate of 400 quintillion pengö to 1 forint, which eventually stabilized the economy. — Encyclopedia Britannica, 14 Apr. 2026 With systems like Oak Ridge National Laboratory's Frontier achieving over a quintillion operations per second, supercomputing has now entered the exascale era. — Chuck Brooks, Forbes.com, 14 May 2026 See All Example Sentences for quintillion

Word History

Etymology

Latin quintus + English -illion (as in million)

First Known Use

circa 1690, in the meaning defined above

Time Traveler
The first known use of quintillion was circa 1690

Rhymes for quintillion

See All Rhymes for quintillion

Browse Nearby Words

Quintillian
quintillion
quintillionth
See all Nearby Words

Cite this Entry

“Quintillion.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/quintillion. Accessed 7 Jul. 2026.

Copy Citation

Kids Definition

quintillion

noun
quin·​til·​lion kwin-ˈtil-yən How to pronounce quintillion (audio)
US : a number equal to 1 followed by 18 zeros see number
also, British : a number equal to 1 followed by 30 zeros see number

More from Merriam-Webster on quintillion

Nglish: Translation of quintillion for Spanish Speakers

Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

Popular in Grammar & Usage

See More

Is that lie 'bald-faced' or 'bold-faced'?

'A' or 'an'? What about before 'h'? An Indefinite Article Guide

Why is '-ed' sometimes pronounced at the end of a word?

Commonly Misspelled Words

How to Use Em Dashes (—), En Dashes (–) , and Hyphens (-)
See More

Popular in Wordplay

See More

14 Phobias You Probably Haven't Heard Of

The Longest Long Words List

One-Word Oxymorons: Bittersweet, Spendthrift, and More

Ten Words Ending with a Silent ‘T’

12 Lovely and Unusual Words for the Natural World
See More

Popular

See More

Is that lie 'bald-faced' or 'bold-faced'?

14 Phobias You Probably Haven't Heard Of

The Longest Long Words List
See More

Games & Quizzes

See All
Play Quordle: Guess all four words in a limited number of tries. Each of your guesses must be a real 5-letter word.
Quordle Can you solve 4 words at once?
Play Blossom: Solve today's spelling word game by finding as many words as you can using just 7 letters. Longer words score more points.
Blossom Pick the best words!
Play Missing Letter: a crossword with a twist. Each of the 25 puzzle words start with a different letter of the alphabet. Which letter is missing?
The Missing Letter A daily crossword with a twist
hangman letters and game
Hangman Lightning Round Figure out which word fits in the blanks.
See All