Definition of "eon" in English

noun

1. Eternity, the duration of the universe.

2. An immeasurably or indefinitely long period of time.

3. (US, informal, hyperbolic) A long period of time.

   • It’s been eons since we last saw each other.

4. (astronomy, geology) A period of one billion (short scale, i.e. 1,000,000,000) years.

5. (geology) The longest geochronologic unit, being a period of hundreds of millions of years; subdivided into eras.

6. (Gnosticism, usually spelled aeon or æon) A spirit being emanating from the Godhead.