noon(redirected from Noon o'clock)
Also found in: Dictionary, Thesaurus.
noonThe time of day at which the Sun crosses the local meridian and is at its highest point above the horizon. This time differs from 12.00 local time by up to about 15 minutes before or after midday, the amount – the equation of time – depending on the time of year.
the moment at which, for a given point on earth, the center of the sun (the true sun or the mean sun) is in the upper culmination. The apparent noon corresponds to a meridian transit by the true sun, while mean noon corresponds to a transit by the mean sun. The time at which noon occurs depends on the geographic longitude. Noon begins one hour later for every 15° of longitude to the west.