eon

[ee-uh n, ee-on] /ˈi ən, ˈi ɒn/
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.
Also, aeon.
Origin
see aeon
Examples from the web for eon
  • Psychiatry is a eon behind any such revelation of the untoward ontology of nightmares.
  • We long to hold on to those rituals and traditions of eon that still resonate, while making new meaning from the ether.
British Dictionary definitions for eon

aeon

/ˈiːən; ˈiːɒn/
noun
1.
an immeasurably long period of time; age
2.
a period of one thousand million years
3.
(often capital) (gnosticism) one of the powers emanating from the supreme being and culminating in the demiurge
Word Origin
C17: from Greek aiōn an infinitely long time

eon

/ˈiːən; ˈiːɒn/
noun
1.
the usual US spelling of aeon
2.
(geology) the longest division of geological time, comprising two or more eras
Word Origin and History for eon
n.

1640s, from Latin aeon, from Greek aion "age, vital force, a period of existence, lifetime, generation;" in plural, "eternity," from PIE root *aiw- "vital force, life, long life, eternity" (cf. Sanskrit ayu "life," Avestan ayu "age," Latin aevum "space of time, eternity," Gothic aiws "age, eternity," Old Norse ævi "lifetime," German ewig "everlasting," Old English a "ever, always").

eon in Science
eon
  (ē'ŏn')   
The longest division of geologic time, containing two or more eras.