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
Examples of eon in a Sentence
Recent Examples on the Web
The Southern Everglades and Florida Bay, which for eons had received that water, grew parched, leading to environmental and economic degradation there as well.
—
Bill Kearney, Sun Sentinel, 29 June 2025
The rocks, dated to 4.16 billion years ago, were formed during the Hadean Eon, the oldest geologic eon in Earth’s history.
—Stephanie Edwards, Discover Magazine, 27 June 2025
Some of these radiometric clocks are robust and can withstand the high temperatures and pressures Earth’s crust has endured over the eons, while others are more affected by these processes.
—Katie Hunt, CNN Money, 27 June 2025
Some work over eons—building the bedrock, for example—and some change daily.
—Michelle Williams, Forbes.com, 18 June 2025
See All Example Sentences for eon
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Bill Kearney, Sun Sentinel, 29 June 2025
The rocks, dated to 4.16 billion years ago, were formed during the Hadean Eon, the oldest geologic eon in Earth’s history.
—Stephanie Edwards, Discover Magazine, 27 June 2025
Some of these radiometric clocks are robust and can withstand the high temperatures and pressures Earth’s crust has endured over the eons, while others are more affected by these processes.
—Katie Hunt, CNN Money, 27 June 2025
Some work over eons—building the bedrock, for example—and some change daily.
—Michelle Williams, Forbes.com, 18 June 2025
See All Example Sentences for eon
Cite this Entry
“Eon.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/eon. Accessed 15 Jul. 2025.
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