E. Cobham Brewer 1810–1897. Dictionary of Phrase and Fable. 1898.
Æon (Greek, aion),
eternity, an immeasurable length of time; any being that is eternal. Basilids reckons there have been 365 such æons, or gods; but Valentinius restricts the number to 30. Sometimes written “on.”
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In geology each series of rocks covers an æon, or an indetinite and immeasurable period of time.
s reckons there have been 365 such æons, or gods; but 
