eon
noun
ˈē-ən 
ˈē-ˌän
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
Example Sentences
Recent Examples on the Web Sanctions take a comparative eon in the scheme of war or a humanitarian crisis. 
Robin Wright, The New Yorker, 7 Mar. 2022 During this early period, the Archean eon, life was not yet a major planetary player. Adam Frank, The Atlantic, 19 Feb. 2022 But for the largest museum of natural history in the world, the year-and-a-half-long closure to the public during the Covid-19 pandemic felt like an eon. Nora Mcgreevy, Smithsonian Magazine, 26 May 2021 Twelve years is an eon in information technology time. Paul Krugman, Star Tribune, 21 May 2021 Over a year and a half, or a political eon ago, the focal point of our political discourse was a caravan of migrants trekking through Central America and Mexico in the hopes of winning asylum in the United States. Osita Nwanevu, The New Republic, 3 June 2020 Over eons, the river carved the Grand Canyon and scattered billions of tons of sediment across its delta, flowing into the Sea of Cortez. Ian James, AZCentral.com, 19 Apr. 2020 Its surface is extremely and uniformly red—probably because of organic molecules that formed over eons of steady pummeling by cosmic radiation. Lee Billings, Scientific American, 20 Feb. 2020 Hunter expects to hit $6 million in sales by May, eons ahead of its loftiest projections from January. Kate Knibbs, Wired, 27 Apr. 2020 See More
Robin Wright, The New Yorker, 7 Mar. 2022 During this early period, the Archean eon, life was not yet a major planetary player. Adam Frank, The Atlantic, 19 Feb. 2022 But for the largest museum of natural history in the world, the year-and-a-half-long closure to the public during the Covid-19 pandemic felt like an eon. Nora Mcgreevy, Smithsonian Magazine, 26 May 2021 Twelve years is an eon in information technology time. Paul Krugman, Star Tribune, 21 May 2021 Over a year and a half, or a political eon ago, the focal point of our political discourse was a caravan of migrants trekking through Central America and Mexico in the hopes of winning asylum in the United States. Osita Nwanevu, The New Republic, 3 June 2020 Over eons, the river carved the Grand Canyon and scattered billions of tons of sediment across its delta, flowing into the Sea of Cortez. Ian James, AZCentral.com, 19 Apr. 2020 Its surface is extremely and uniformly red—probably because of organic molecules that formed over eons of steady pummeling by cosmic radiation. Lee Billings, Scientific American, 20 Feb. 2020 Hunter expects to hit $6 million in sales by May, eons ahead of its loftiest projections from January. Kate Knibbs, Wired, 27 Apr. 2020 See More 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
variant of aeon