Etymology tree Proto-Indo-European *me Proto-Indo-European *dʰeh₁-? Proto-Indo-European *-dʰe Proto-Indo-European *médʰi Proto-Indo-European *-os Proto-Indo-European *médʰyos Proto-Italic *meðios Latin medius Proto-Indo-European *dyew- Proto-Indo-European *-s Proto-Indo-European *dyḗws Proto-Italic *djous Latin diēs Latin medīdiēs Latin merīdiēs Proto-Indo-European *-nós Proto-Italic *-nos Proto-Italic *-ānos Latin -ānus Latin merīdiānusder. Middle English meridian English meridian The noun is derived from Late Middle English meridian, meridien (“midday, noon; position of the sun at noon; the south; longitude of a place; (astronomy) celestial meridian”) [and other forms], from Anglo-Norman meridien (“midday”), Middle French meridien (“midday; the south; terrestrial meridian; (astronomy) celestial meridian”) (modern French méridien), and Old French meridiane, meridiiene, and from their etymon Latin merīdiānum (“midday; position of the sun at noon; the south”), a noun use of the neuter form of merīdiānus (“relating to midday; southern”); see further at etymology 1. Sense 1.1 (“celestial meridian”) is ultimately modelled after Latin merīdiāna līnea (“meridian line”). Sense 5.2 (“midday rest; siesta”) is modelled after Late Latin meridiana (“midday; midday rest”), probably short for Latin merīdiāna hōra (“midday time”). The verb is derived from the noun.

noontide • 12 o'clock • 12 noon • 12 p.m. • high noon • meridian • meridiem • midday • nones • noon • noonday • noontime • noon-time • sext • twelve • undern • undermeal • undertide • ACME • elevation • Height • longitude • middle day • Peak • Pinnacle • Prime • Summit • superlative • tiptop • Top • two-line double pica