nychthemeron means A period of one day and one night, a date: in the West, a period of 24 consecutive hours. Lexicurio rates it Sui generis — a strength score of 90 out of 100.
nychthemeron is pronounced /nɪkˈθɛm.ə.ɹɒn/.
Why “nychthemeron” is a great word
NYCHTHEMERON — [Noun] A continuous 24-hour cycle encompassing one full day and night. From Ancient Greek νυχθήμερον (nukhthēmeron), noun use of the neuter of νυχθήμερος (nukhthēmeros, "lasting a day and night"), from νύξ (nux, "night") + ἡμέρα (hēmera, "day"). Unlike "day," which typically denotes only the sunlit hours, or "calendar day," which binds the cycle to a civil midnight, the nychthemeron is the raw, astronomical unit of time, unmoored from human schedules. It is the exact arc from a first star to the next, the circadian rhythm of a creature in a cave, and the unbroken vigil beside a sickbed—the fundamental, indifferent pulse upon which we hang our invented schedules.
noun
- A period of one day and one night, a date: in the West, a period of 24 consecutive hours.“It has not yet been found by Observation, whether Mercury turns upon its own Axis, ... that is, whether it has the vicissitude of Day and Night, much less what is the space of its Nychthemeron or Natural Day; but one may safely enough conjecture that it does revolve about its Axis, since the other Planets do.”