eon

noun \ ˈē-ən , ˈē-ˌän \

variants: or chiefly British aeon

|Updated on: 11 Jun 2018

Definition of eon

1 : an immeasurably or indefinitely long period of time : age

I haven't seen him in eons.

2 a : 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

See eon defined for English-language learners

Recent Examples of eon from the Web

An eon or two ago, Eastman Kodak was a bleeding-edge technology company.

— kevin roose, New York Times, "Kodak’s Dubious Cryptocurrency Gamble," 30 Jan. 2018
With each brushstroke, grain by grain, they are transported back through the eons, as a distant lizard roars.

— mark washburn, charlotteobserver, "The Dinosaur King in the Queen City? Charlotte kids might not believe the size of this experience | Charlotte Observer," 25 May 2018
The audience is the bee audience, with the spellers on bleachers on stage in a school gymnasium, the judges at a table eon the other side.

— laura demarco, cleveland.com, ""The 25th Annual Putnam County Spelling Bee" is poignant and F-U-N (review)," 21 Apr. 2018
For eons, plants were, of course, the primary treatment for most illnesses.

— Scientific American, "In Medicine and Skincare, Plants are Staging a Comeback," 4 May 2018
The eons-old erosion resulted in a wonderland of waterfalls, including five of the world's tallest; polished domes; toothy peaks; and precipitous cliffs.

— andrea sachs, chicagotribune.com, "This summer, stop by the 23 U.S. locales that have risen to become UNESCO World Heritage sites," 4 May 2018
June, in the present, is eons away from handmaid’s training camp and from her mother.

— refinery29.com, "The Handmaid's Tale Season 2, Episode 3 Recap: Ain't No Hollaback Girl," 2 May 2018
In that sense, the game felt eons away from where this program was a year ago.

— shawn windsor, Detroit Free Press, "Michigan State football eons away from where it was in 2017," 7 Apr. 2018
Horn-faced dinosaurs like Triceratops had elaborate frills and spurs that adorned their skulls and grew more elaborate—and diverse—through the eons.

— gretchen vogel, Science | AAAS, "What made Triceratops so horny?," 20 Mar. 2018

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.

Origin and Etymology of eon

Latin, from Greek aiōn — more at ³aye

NEW! Time Traveler

First Known Use: circa 1642

in the meaning defined at sense 1

See Words from the same year

Other Geology Terms

anthracite, boulder, cwm, erratic, igneous, intrusive, mesa, sedimentary, silt, swale

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