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

South American hunter-gatherers have alternated rest days with days full of movement for eons. —Matt Fuchs, TIME, 30 Sep. 2024

Fewer still make it through the eons in particularly good shape. —Asher Elbein, Scientific American, 24 Sep. 2024

The set is a welcome step up from the disintegrating nail file she's had for eons and the signature orange Hermès box is a serotonin boost in and of itself. —Sarah Han and Annie Blackman, Allure, 14 Sep. 2024

For eons, the regular movements of the sun and moon have set the pace for all of life on Earth. —Allison Parshall, Scientific American, 11 Sep. 2024

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