Definition of aeon in English:


Line breaks: aeon
Pronunciation: /ˈiːən
(US or • technical also eon)


  • 1 (often aeons) An indefinite and very long period of time: he reached the crag aeons before I arrived
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    • It is ages and aeons since I have been to the Hills.
    • I'll spend aeons staring at bottles of expensive shampoo humming ‘Maybe this time’.
    • Just after that, she started going out with a mutual friend of ours, who I'd dated aeons ago and was still friendly with.
  • 1.1 Astronomy & Geology A unit of time equal to a thousand million years.
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    • Because they have succumbed to erosion and weathering, perhaps for aeons, these craters are notoriously difficult to spot.
    • It's a rock place, a world of eons and eras and millions of years conflated to timelessness.
    • Over the eons the lunar spin rate has been damped by Earth's gravity, because the Moon's mass distribution is not uniform.
  • 1.2 Geology A major division of geological time, subdivided into eras: the Precambrian aeon
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    • The record has been much deformed, reconstituted, and obliterated during the subsequent Proterozoic and Phanerozoic eons.
    • The rocks dated back into the Archean eon, before 2.5 billion years ago.
    • These creatures were direct descendants of the great dinosaurs of the long past Mesozoic Aeon.
  • 2 Philosophy (In Neoplatonism, Platonism, and Gnosticism) a power existing from eternity; an emanation or phase of the supreme deity.
    More example sentences
    • He goes on to note that all aeons emanate from it.
    • This aeon is the image of the eternal age of the next life.
    • Whether that master be regarded as a sage or as a Gnostic aeon, the orthodox view of him would be seriously challenged.


mid 17th century: via ecclesiastical Latin from Greek aiōn 'age'.

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