Noun

• S: (n) eon, aeon (the longest division of geological time)
• part meronym
• has instance
• direct hypernym / inherited hypernym / sister term
• S: (n) geological time, geologic time (the time of the physical formation and development of the earth (especially prior to human history))
• direct hyponym / full hyponym
• S: (n) eon, aeon (the longest division of geological time)
• S: (n) period, geological period (a unit of geological time during which a system of rocks formed) "ganoid fishes swarmed during the earlier geological periods"
• S: (n) ice age, glacial period, glacial epoch (any period of time during which glaciers covered a large part of the earth's surface) "the most recent ice age was during the Pleistocene"
• S: (n) Quaternary, Quaternary period, Age of Man (last 2 million years)
• S: (n) Tertiary, Tertiary period (from 63 million to 2 million years ago)
• S: (n) Cretaceous, Cretaceous period (from 135 million to 63 million years ago; end of the age of reptiles; appearance of modern insects and flowering plants)
• S: (n) Jurassic, Jurassic period (from 190 million to 135 million years ago; dinosaurs; conifers)
• S: (n) Triassic, Triassic period (from 230 million to 190 million years ago; dinosaurs, marine reptiles; volcanic activity)
• S: (n) Permian, Permian period (from 280 million to 230 million years ago; reptiles)
• S: (n) Carboniferous, Carboniferous period (from 345 million to 280 million years ago)
• S: (n) Pennsylvanian, Pennsylvanian period, Upper Carboniferous, Upper Carboniferous period (from 310 million to 280 million years ago; warm climate; swampy land)
• S: (n) Mississippian, Missippian period, Lower Carboniferous, Lower Carboniferous period (from 345 million to 310 million years ago; increase of land areas; primitive ammonites; winged insects)
• S: (n) Devonian, Devonian period, Age of Fishes (from 405 million to 345 million years ago; preponderance of fishes and appearance of amphibians and ammonites)
• S: (n) Silurian, Silurian period (from 425 million to 405 million years ago; first air-breathing animals)
• S: (n) Ordovician, Ordovician period (from 500 million to 425 million years ago; conodonts and ostracods and algae and seaweeds)
• S: (n) Cambrian, Cambrian period (from 544 million to about 500 million years ago; marine invertebrates)
• S: (n) era, geological era (a major division of geological time; an era is usually divided into two or more periods)
• S: (n) epoch (a unit of geological time that is a subdivision of a period and is itself divided into ages)
• direct hypernym / inherited hypernym / sister term
• derivationally related form
• W: (adj) eonian [Related to: eon] (of or relating to a geological eon (longer than an era))
• W: (adj) aeonian [Related to: aeon] (of or relating to a geological eon (longer than an era))
• S: (n) eon, aeon (an immeasurably long period of time) "oh, that happened eons ago"
• direct hypernym / inherited hypernym / sister term
• derivationally related form
• S: (n) eon, aeon ((Gnosticism) a divine power or nature emanating from the Supreme Being and playing various roles in the operation of the universe)