1911 Encyclopædia Britannica/Noon

NOON, midday, twelve o’clock. The O. Eng. nón, Nor. non, Dutch noen, are all from Lat. nona sc. hora, the ninth hour, i.e. according to the Roman system, three o’clock p.m. (see Day). The early uses of noon till the 13th and 14th centuries are either as translating the Latin, especially with reference to the Crucifixion, or as equivalent to the canonical hour of “nones” (see Breviary). The ordinary word for twelve o’clock was middæg, midday, also the equivalent of the canonical hour “sext.” Both the office and the meal taken about that time were shifted to an earlier hour, and by the 14th century the ordinary use of “noon” is that current to-day.

For “nones” (i.e. nonae, sc. dies) in the Roman calendar, see Calendar.