(Greek, aion), eternity, an immeasurable length of time; any being that is eternal. Basilides reckons there have been 365 such æons, or gods; but Valentinius restricts the number to 30. Sometimes written “eon.”
In geology each series of rocks covers an æon, or an indefinite and immeasurable period of time.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894
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