noun, often attributive
sep·​til·​lion | \ sep-ˈtil-yən How to pronounce septillion (audio) \

Definition of septillion

US : a number equal to 1 followed by 24 zeros — see Table of Numbers also, British : a number equal to 1 followed by 42 zeros — see Table of Numbers

Examples of septillion in a Sentence

Recent Examples on the Web Authorities say the match Parabon Labs identified had a 1 in 65 septillion odds of being inaccurate. Grace Kahng, ABC News, 16 Sep. 2021 By comparison, the pressure inside a neutron star is in the septillions of gigapascals, so these liquid cases likely occur in nature around the universe. Caroline Delbert, Popular Mechanics, 9 Dec. 2019 The number of possible routes adds up to around 15 septillion (trillion trillion), according to Goldman Sachs, an investment bank. The Economist, 28 Mar. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'septillion.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

See More

First Known Use of septillion

1690, in the meaning defined above

History and Etymology for septillion

French, from Latin septem + French -illion (as in million) — more at seven

Learn More About septillion

Time Traveler for septillion

Time Traveler

The first known use of septillion was in 1690

See more words from the same year

Dictionary Entries Near septillion




See More Nearby Entries 

Statistics for septillion

Last Updated

29 Sep 2021

Cite this Entry

“Septillion.” Dictionary, Merriam-Webster, Accessed 26 Nov. 2021.

Style: MLA
MLACheck Mark Icon ChicagoCheck Mark Icon APACheck Mark Icon Merriam-WebsterCheck Mark Icon


Test Your Vocabulary

Difficult Spelling Words Quiz

  • alphabet pasta spelling help
  • Which is the correct spelling?
Name That Thing

Test your visual vocabulary with our 10-question challenge!

Love words? Need even more definitions?

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