where did the term high noon come from
Noon Solar noon (informally high noon)[3] is the moment when the Sun contacts the observer's meridian, reaching its highest position above the horizon on that day ("Sun transit time"). This is also the origin of the terms ante meridiem (a.m.) and post meridiem (p.m.), as noted below. The Sun is directly overhead at solar noon at the Equator on the equinoxes, at the Tropic of Cancer (latitude 23°26′13.0″ N) on the June solstice and at the Tropic of Capricorn (23°26′13.0″ S) on the December solstice. In the Northern Hemisphere, north of the Tropic of Cancer, the Sun is due south of the observer at solar noon; in the Southern Hemisphere, south of the Tropic of Capricorn, it is due north.
12-hour clock The 12-hour clock can be traced back as far as Mesopotamia and Ancient Egypt.[4] Both an Egyptian sundial for daytime use[5] and an Egyptian water clock for night-time use were found in the tomb of Pharaoh Amenhotep I.[6] Dating to c. 1500 BC, these clocks divided their respective times of use into 12 hours each.