nychthemeron

noun

nych·​them·​er·​on

variants or less commonly nycthemeron

⸗ˈ⸗məˌrän

plural nychthemera

-m(ə)rə

or nychthemerons

: a full period of a night and a day

Word History

Etymology

Greek nychthēmeron, from nykt-, nyx night + -hēmeron (from hēmera day)

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