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

For eons, these creatures have thrived across the azure waters of the Maldives—and in the modern era, the Manta Retreat provides the perfect opportunity to marvel at these splendid fish in the flesh. —Jared Ranahan, Forbes, 24 Jan. 2025

The main ingredient in Immy, this beneficial bacteria is derived from soil and has helped humans for eons by reducing chronic inflammation. —Emily Orofino, Vogue, 24 Jan. 2025

These were studied and, if not intentionally, were thought about as works of scale, as were the patterns on a butterfly wing, which are composed of millions of scales, grandiose designs developed over eons. —Alexis Wright, Harper's Magazine, 2 Jan. 2025

Though that might seem like eons from now, much of the franchise is streaming on Netflix and ready for a movie marathon. —Declan Gallagher, EW.com, 20 Nov. 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