aeon -
n. (also eon)
1 a very long or indefinite period.
2 an age of the universe.
3 Astron. a thousand
million years.
4 an eternity.
5 Philos. (in Neoplatonism, Platonism,
and Gnosticism) a power existing from eternity, an emanation or phase of the supreme deity.
[eccl.L f. Gk aion age] 
