\ ˈē-ən How to pronounce eon (audio) , ˈē-ˌän How to pronounce eon (audio) \
variants: or chiefly British

Definition of eon

1 : an immeasurably or indefinitely long period of time : age I haven't seen him in eons.
2a : a very large division of geologic time usually longer than an era the Archean eon
b : a unit of geologic time equal to one billion years

Examples of eon in a Sentence

Recent Examples on the Web But for the largest museum of natural history in the world, the year-and-a-half-long closure to the public during the Covid-19 pandemic felt like an eon. Nora Mcgreevy, Smithsonian Magazine, 26 May 2021 Twelve years is an eon in information technology time. Paul Krugman, Star Tribune, 21 May 2021 Over a year and a half, or a political eon ago, the focal point of our political discourse was a caravan of migrants trekking through Central America and Mexico in the hopes of winning asylum in the United States. Osita Nwanevu, The New Republic, 3 June 2020 Over eons, the river carved the Grand Canyon and scattered billions of tons of sediment across its delta, flowing into the Sea of Cortez. Ian James, AZCentral.com, 19 Apr. 2020 Its surface is extremely and uniformly red—probably because of organic molecules that formed over eons of steady pummeling by cosmic radiation. Lee Billings, Scientific American, 20 Feb. 2020 Hunter expects to hit $6 million in sales by May, eons ahead of its loftiest projections from January. Kate Knibbs, Wired, 27 Apr. 2020 The New Yorker published my earliest effort, eons back, in 1974. Deborah Treisman, The New Yorker, 27 Apr. 2020 Time feels increasingly pointless now in these weeks (months? eons?) of stay-at-home, never-get-dressed, dinner-at-3-p.m. Judge John Hodgman, New York Times, 23 Apr. 2020

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

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First Known Use of eon

circa 1642, in the meaning defined at sense 1

History and Etymology for eon

borrowed from Late Latin aeōn "age (in the world's history), evil spirit (in Gnosticism)," borrowed from Greek aiṓn "lifetime, long period of time, age" — more at aye entry 3

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Cite this Entry

“Eon.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/eon. Accessed 24 Jan. 2022.

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More Definitions for eon



English Language Learners Definition of eon

: a very long period of time


Kids Definition of eon

variant of

More from Merriam-Webster on eon

Nglish: Translation of eon for Spanish Speakers

Britannica English: Translation of eon for Arabic Speakers

Britannica.com: Encyclopedia article about eon


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