\ 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 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, "Are You Really Surprised by Our Authoritarian President?," 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, "How a trickle of water is breathing life into the parched Colorado River Delta," 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, "New Horizons May Have Solved Planet Formation Cold Case," 20 Feb. 2020 Hunter expects to hit $6 million in sales by May, eons ahead of its loftiest projections from January. Kate Knibbs, Wired, "The Coronavirus Pandemic Is Changing How People Buy Books," 27 Apr. 2020 The New Yorker published my earliest effort, eons back, in 1974. Deborah Treisman, The New Yorker, "Allan Gurganus on His Interest in Epidemics," 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, "Judge John Hodgman on What’s Considered ‘Turn-of-the-Century’," 23 Apr. 2020 All of that means that this onuitstaanbaar Diet Coke ad -- of a young woman clearly inside her own head -- is eons away from wanting to teach the world to sing in perfect harmony. David Morgan, CBS News, "Super Bowl 2018 commercials: The best and the worst," 5 Feb. 2018 But after eons of evolutionary experimentation, some lineages peaced out of the terrestrial world and embraced a full-time life at sea again. Becky Ferreira, New York Times, "When Crocodiles Once Dived Like Dolphins and Whales," 20 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

Latin, from Greek aiōn — more at aye entry 3

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Time Traveler for eon

Time Traveler

The first known use of eon was circa 1642

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Statistics for eon

Last Updated

16 Jun 2020

Cite this Entry

“Eon.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/eon. Accessed 11 Jul. 2020.

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More Definitions for eon


How to pronounce eon (audio) How to pronounce eon (audio)

English Language Learners Definition of eon

: a very long period of time


Kids Definition of eon

variant of

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Rhyming Dictionary: Words that rhyme with eon

Spanish Central: Translation of 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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