hem·​era | \ ˈhemərə\
plural hemerae\ -​ə(ˌ)rē \ also hemera

Definition of hemera

1 : a stratigraphic zone comprising the time range of a particular fossil species
2 : a period of time during which a race of organisms is at the apex of its evolution

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History and Etymology for hemera

New Latin, from Greek hēmera day; akin to Greek ēmar day, Armenian aur

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tremendous in size, volume, or degree

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