aeon
noun /ˈiːən/,  /ˈiːɒn/
  /ˈiːən/,  /ˈiːɑːn/
 (British English) (North American English or specialist eon)
 - (formal) an extremely long period of time; thousands of years- Only yesterday—and it seemed aeons ago, not just a few hours—he had been a happily married man.
 
- (geology) a major division of time, divided into eras- aeons of geological history
- These hills have been worn down over aeons of geological time.
 
Word Originmid 17th cent.: via ecclesiastical Latin from Greek aiōn ‘age’.