English > eon: 3 senses > noun 1, time| Meaning | The longest division of geological time. |
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| Synonym | aeon |
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| Instances | Archean, Archean eon, Archean aeon, Archeozoic, Archaeozoic, Archeozoic eon, Archaeozoic aeon | The time from 3,800 million years to 2,500 million years ago |
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| Hadean, Hadean time, Hadean eon, Hadean aeon, Priscoan, Priscoan eon, Priscoan aeon | The earliest eon in the history of the Earth from the first accretion of planetary material (around 4,600 million years ago) until the date of the oldest known rocks (about 3,800 million years ago) |
| Phanerozoic, Phanerozoic eon, Phanerozoic aeon | The period from about 5,400 million years ago until the present |
| Precambrian, Precambrian eon, Precambrian aeon, Precambrian period | The eon following the Hadean time and preceding the Phanerozoic eon |
| Proterozoic, Proterozoic eon, Proterozoic aeon | From 2,500 to 544 million years ago |
| Parts | era, geological era | A major division of geological time |
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| Broader | geological time, geologic time | The time of the physical formation and development of the earth (especially prior to human history) |
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| Spanish | eon, eón, evo |
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| Catalan | eó |
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| Adjectives | eonian, aeonian | of or relating to a geological eon (longer than an era) |
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