from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A period of one day and one night, a date: in the West, this is a period of 24 consecutive hours.
from The Century Dictionary and Cyclopedia
- n. The whole natural day, or day and night, consisting of twenty-four hours.
From Ancient Greek νυχθήμερον (nukhthemeron), noun use of the neuter singular form of νυχθήμερος ("lasting a day and night"), from νύξ (nuks, "night") + ἡμέρα (hēmera, "day"). (Wiktionary)