Midday

Noon (also midday or noon time) is usually defined as 12 o'clock in the daytime, as opposed to midnight (calling noon 12 p.m. (i.e. 12 after midday), although common, is wrong). The term midday is also used colloquially to refer to an arbitrary period of time in the middle of the day. Solar noon is when the Sun transits the local celestial meridian and is at its highest altitude in the sky, at 12 o'clock apparent solar time. The local or clock time of solar noon depends on the longitude and date. The opposite of noon is midnight.

In many cultures in the Northern Hemisphere, noon had ancient geographic associations with the direction "south" (as did midnight with "north" in some cultures). Remnants of the noon = south association are preserved in the words for noon in French (Midi) and Italian (Mezzogiorno), both of which also refer to the southern parts of the respective countries. Modern Polish, Belarusian, Ukrainian, and Serbian go a step farther, with the words for noon (południe, поўдзень, південь, пoднe – literally "half-day") also meaning "south" and the words for "midnight" (północ, поўнач, північ, пoнoħ – literally "half-night", as with English mid(dle) meaning "half") also meaning "north".

The word noon is derived from Latin nona hora, the ninth hour of the day, and is related to the liturgical term none. The Roman and Western European medieval monastic day began at 6:00 a.m. (06:00) at the equinox by modern timekeeping, so the ninth hour started at what is now 3:00 p.m. (15:00) at the equinox. In English, the meaning of the word shifted to midday and the time gradually moved back to 12:00 local time (that is, not taking into account the modern invention of time zones). The change began in the 12th century and was fixed by the 14th century.

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