from the GNU version of the Collaborative International Dictionary of English
- n. the mean solar day, used in the ordinary reckoning of time, and among most modern nations beginning at mean midnight; its hours are usually numbered in two series, each from 1 to 12. This is the period recognized by courts as constituting a day. The Babylonians and Hindoos began their day at sunrise, the Athenians and Jews at sunset, the ancient Egyptians and Romans at midnight.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a day reckoned from midnight to midnight
Sorry, no etymologies found.