eon
/ˈiːɑn/
noun
- An extremely long, indefinite period of time; thousands or millions of years.
- Geologists study changes that happen over eons.
- The stars have been shining for eons.
- It felt like an eon before the bus finally arrived.
- The largest division of geological time, lasting hundreds of millions of years.
- The Precambrian eon covers most of Earth's history.
- Dinosaurs lived during the Phanerozoic eon.
- Rocks from the Archean eon are among the oldest on Earth.