eon
Eternity, the duration of the universe.
Other meanings
An immeasurably or indefinitely long period of time.
A period of one billion (short scale, i.e. 1,000,000,000) years; a gigayear.
Word history
From Ancient Greek "αἰών" (age, era).
Where this comes from
This definition is adapted from “eon” on Wiktionary, by its contributors, published under CC BY-SA 4.0. This page is published under the same licence.