civil day

This difference from the civil day often leads to confusion.

That's what we paid in more civil days when somebody said, "Can you spare a dime for a cup of coffee?"

To keep the civil day aligned with the apparent movement of the Sun, positive or negative leap seconds may be inserted.

Hindu chronology divides the civil day (daylight hours) into vipalas, palas and ghatikas.

Although the civil day began at midnight and by civil time it was still Saturday, by nautical time Sunday began at noon.

In ordinary usage, the civil day is reckoned by the midnight epoch, that is, the civil day begins at midnight.

The present common convention has the civil day starting at midnight, which is near the time of the lower culmination of the mean Sun on the central meridian of the time zone.

A civil day is usually also 86,400 seconds, plus or minus a possible leap second in Coordinated Universal Time UTC, and, in some locations, occasionally plus or minus an hour when changing from or to daylight saving time.

In older astronomical usage, it was usual, until 1 January 1925, to reckon by a noon epoch, 12 hours after the start of the civil day of the same denomination, so that the day began when the mean sun crossed the meridian at noon.

To complicate the whole system, the day began at midnight for the flag signals (corresponding to the civil day), while it began at noon for the night signals, and thus corresponded with the noon-to-noon nautical day used in the logs and journals.

In 1935, the term Universal Time was recommended by the International Astronomical Union as a more precise term than Greenwich Mean Time, because GMT could refer to either an astronomical day starting at noon or a civil day starting at midnight.

That this universal day is to be a mean solar day; is to begin for all the world at the moment of mean midnight of the initial meridian, coinciding with the beginning of the civil day and date of that meridian; and is to be counted from zero up to twenty-four hours.