Etymology: < Anglo-Norman meridien midday, the south, and Middle French meridien the south (c1170 in Old French), celestial and terrestrial meridian (1546; 1377 in form meridian ; French méridien ), and their etymon classical Latin merīdiānum midday, the position of the sun at midday, the south, use as noun of neuter of merīdiānus meridian adj. Compare meridional adj. and n. Compare also ancient Greek μεσημβρία midday, the south (see Mesembryanthemum n.), and its corresponding adjective μεσημβρινός relating to midday, southern, also used as noun in sense 3.In sense 2c after post-classical Latin meridiana noon, siesta (early 11th cent., probably short for classical Latin merīdiāna hōra ; from late 11th cent. in British sources). Compare Old French meridiane (c1240), meridienne (1213 in phrase dormir a meridienne ) midday, French méridienne midday rest, siesta (1680), and merion n. (In quot. a1450 at sense 2c translating post-classical Latin somno meridiano, ablative of somnus meridianus (see meridian adj.).) In sense 3a(a) ultimately after classical Latin merīdiāna līnea (in Vitruvius in directions for how to draw up a circle or octagon of the winds; from 13th cent. in post-classical Latin in British sources); compare later meridian line n. at meridian adj. Compounds. With celestial meridian compare French méridien céleste (1765); with terrestrial meridian compare French méridien terrestre (1701). In quot. 1607 at sense 4c meridian apparently translates Hellenistic Greek ἡλικία prime of life (Clemens Alexandrinus Paedagogus 2. 2. 20. 3). In sense 6 after German Meridian or French méridien (both c1957 in this sense: see quot. 1959 at sense 6), themselves after Chinese jīng channels (also used in senses ‘warp’, ‘longitude’).

Etymology: < Middle French meridien of midday (c1280 in Old French as meridiane ; compare Anglo-Norman meridien ), southern (1529; French méridien ), and their etymon classical Latin merīdiānus relating to midday, southern < merīdiēs midday, the south ( < early Latin medīdiēs , with dissimilation of -d- to -r- (cited by Varro; compare Cicero, Orator 47.158 ‘ipsum meridiem cur non medidiem? credo, quod erat insuavius’) < medius middle (see medium n. and adj.) + diēs day: see diurnal adj. and n.) + -ānus -an suffix. Compare slightly earlier meridional adj.In phrase devil meridian (see quots. c1540 at sense 1a, 1551 at sense 1a) after post-classical Latin daemonium meridianum (Vulgate, corresponding to Hellenistic Greek δαιμόνιον μεσημβρινόν in the Septuagint: see note below); compare Anglo-Norman diable meridien (first half of the 12th cent.). With meridian sleep, meridian slumber compare classical Latin somnus meridiānus. With meridian hour compare classical Latin merīdiāna hōra, Old French eure meridiane (c1280). With meridian sun compare classical Latin merīdiānus sōl, Middle French soleil meridien (1542).

Etymology: < meridian n.