aeon

 
Pronunciation: /ˈiːən/
(US or technical also eon)

noun

  • 1 (often aeons) an indefinite and very long period of time: he reached the crag aeons before I arrived
  • Astronomy & Geology a unit of time equal to a thousand million years.
  • Geology a major division of geological time, subdivided into eras: the Precambrian aeon
  • 2 Philosophy (in Neoplatonism, Platonism, and Gnosticism) a power existing from eternity; an emanation or phase of the supreme deity.

Origin:

mid 17th century: via ecclesiastical Latin from Greek aiōn 'age'