eon

or ae·on

[ ee-uhn, ee-on ]

noun

1. an indefinitely long period of time; age.
2. the largest division of geologic time, comprising two or more eras.
3. Astronomy. one billion years.

eon

/ ˈiːən; ˈiːɒn /

noun

1. the usual US spelling of aeon
2. geology the longest division of geological time, comprising two or more eras

eon

/ ē′ŏn′ /

1. The longest division of geologic time , containing two or more eras.

Word History and Origins

Origin of eon¹

aeon