Eon — Science definition
The largest unit of geologic time; Earth's history is divided into a few eons, with the Phanerozoic being the most recent.
Where it is taught
- Geologic Time & the Rock Record — Earth’s History, Earth & Space Science, Grade 9
In use
That recent, life-filled slice is the Phanerozoic eon, and it splits into three eras, each bookended by dramatic turning points in the history of life.
Geologic Time & the Rock Record