eon

noun

ˈē-ən  ˈē-ˌän 

variants or chiefly British aeon

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

Examples of eon in a Sentence

Recent Examples on the Web

The Lemont limestone story begins eons before there was a Chicago with a Water Tower and Holy Name Cathedral, both built with locally mined stone that slowly turns from white to yellowish. —Ron Grossman, Chicago Tribune, 17 Sep. 2023

For eons, the river was a wild, unpredictable force that shaped this landscape. —Janet Wilson, ProPublica, 9 Nov. 2023

Their astronomical sleuthing continues, including examining lunar craters that have remained essentially undisturbed for eons. —WIRED, 1 Nov. 2023

Life has a physiological ceiling—a temperature that even eons of evolution cannot allow an animal to tolerate. —Katherine J. Wu, The Atlantic, 17 Aug. 2023

The Less threaten to make extinct the Fewer who for eons have lived simple, earnest lives dedicated to accurate portrayals of amounts and counts that are not absolute. —John Kelly, Washington Post, 21 Oct. 2023

At some point through the long eons of history, bed bugs (or Cimex lectularius, as scientists have named them) eventually added us to their diet — bats are commonly pointed to as the creature that exposed humans to the bloodthirsty insect. —Stephen C. George, Discover Magazine, 18 Sep. 2023

Most exciting are artisanal products whose designers approach engineering challenges with clean-sheet solutions, or just as exciting, with technology that has been forgotten for eons and is being newly reimagined. —Robert Ross, Robb Report, 21 Sep. 2023

Their makers are creatures like humans on Earth, albeit the products of different evolution and eons ahead in terms of scientific progress. —The Salt Lake Tribune, 5 Sep. 2023

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Word History

Etymology

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

First Known Use

circa 1642, in the meaning defined at sense 1

Kids Definition

eon

noun

ˈē-ən

1

: a very long period of time

2

a

: a very large division of geologic time usually longer than an era

b

: a unit of geologic time equal to one billion years