eon (redirected from Eon (disambiguation))

eon

Long span of geologic time. In formal usage, eons are the longest portions of geologic time (eras are the second-longest). Three eons are recognized: the Phanerozoic Eon (dating from the present back to the beginning of the Cambrian Period), the Proterozoic Eon, and the Archean Eon. Less formally, eon often refers to a span of one billion years.

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aeon (esp US), eon

1. a period of one thousand million years

2. Gnosticism one of the powers emanating from the supreme being and culminating in the demiurge

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eon [′ē‚än]

(mechanics)

A unit of time, equal to 10⁹years.