eon

or ae·on

[ ee-uh n, ee-on ]
/ ˈi ən, ˈi ɒn /

noun

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

Origin of eon

see origin at aeon
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

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British Dictionary definitions for eon

eon

/ (ˈiːən, ˈiːɒn) /

noun

the usual US spelling of aeon
geology the longest division of geological time, comprising two or more eras
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Science definitions for eon

eon

[ ēŏn′ ]

The longest division of geologic time, containing two or more eras.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.