Online Etymology Dictionary

merrymaking (n.): also merry-making, 1714; see merry + make (v.). Related: Merry-maker (1827).
merrythought (n.): "wishbone," c.1600, from merry (adj.) + thought. Also cf. wishbone.
mesa (n.): "high table land," 1759, from Spanish mesa "plateau," literally "table," from Latin mensa "table" (source of Rumanian masa, Old French moise "table").
mesalliance (n.): "marriage with a person of lower social position," 1782, from French mésalliance, from pejorative prefix mes- (from Latin mis-; see mis-) + alliance (see alliance).
mescal (n.): "plant of the genus Agave," found in deserts of Mexico and southwestern U.S., especially the American aloe, or maguey plant, 1702, from Mexican Spanish, from Nahuatl (Aztec) mexcalli "fermented drink made from agave," from metl "agave" + ixcalli "stew." Meaning "intoxicating liquor from fermented juice of the agave" is attested in English from 1828. Also the name of a small desert cactus (peyote) found in northern Mexico and southern Texas (1885).
mescaline (n.): crystalline alkaloid, 1896, from German mezcalin (1896), so called because it originally was found in the buttons that grow atop the mescal cacti (see mescal). With chemical suffix -ine (2).
mesdames: plural of French madame (see madam).
meseems: late 14c., me semeth, from me (pron.) + seem (v.).
mesel: "leprous" (adj.); "a leper" (n.); both c.1300, from Old French mesel "wretched, leprous; a wretch," from Latin misellus "wretched, unfortunate," as a noun, "a wretch," in Medieval Latin, "a leper," diminutive of miser "wretched, unfortunate, miserable" (see miser). Also from Latin misellus are Old Italian misello "sick, leprous," Catalan mesell "sick."
mesenteritis (n.): "inflammation of the mesentery," 1802; see mesentery + -itis.
mesentery (n.): fold of the peritoneum, early 15c., from medical Latin mesenterium "middle of the intestine," from medical Greek mesenterion, from mesos "middle" (see medial (adj.)) + enteron "intestine" (see enteric). Related: Mesenteric.
mesh (n.): late 14c., mesche, "open space in a net," probably from late Old English max "net," earlier mæscre, from Proto-Germanic *mask- (cf. Old Norse möskvi, Danish maske, Swedish maska, Old Saxon masca, Middle Dutch maessce, Dutch maas "mesh," Old High German masca, German Masche "mesh"), from PIE root *mezg- "to knit, plait, twist" (cf. Lithuanian mezgu "to knit," mazgas "knot").
mesh (v.): 1530s, originally in the figurative sense of "entangle, involve," from mesh (n.). Literal sense "to become enmeshed" is from 1580s. Meaning "to fit in, combine" is from 1944. Related: Meshed; meshing.
meshuga (adj.): "mad, crazy, stupid," 1892, from Hebrew meshugga, part. of shagag "to go astray, wander." The adjective has forms meshugener, meshugenah before a noun.
mesial (adj.): "middle, median," 1803, an irregular formation from Greek mesos "middle" (see meso-) + -al (1). Related: Mesially.
mesic (adj.): 1926, in ecology sense, from Greek mesos "middle" (see meso-) + -ic. From 1939 in physics (from meson).
mesmeric (adj.): "pertaining to mesmerism," 1829; see mesmerism + -ic.
mesmerise (v.): chiefly British English spelling of mesmerize (v.); for suffix, see -ize. Related: Mesmerised; mesmerising.
mesmerism (n.): "hypnotism," 1802, from French mesmérisme, named for Franz Anton Mesmer (1734-1815), Austrian physician who developed a theory of animal magnetism and a mysterious body fluid which allows one person to hypnotize another. Related: Mesmerist.
mesmerize (v.): 1829, back-formation from mesmerism. Transferred sense of "enthrall" is first attested 1862. Related: Mesmerized; mesmerizing.
mesne (adj.): mid-15c., "mean;" altered spelling (by French influence) of Anglo-French meen "mean" (Old French meien "middle;" see mean (adj.); also cf. demesne).
meso-: word-forming element meaning "middle, intermediate, halfway," sometimes mes- before vowels, comb. form of Greek mesos "middle, in the middle; middling, moderate; between" (see medial (adj.)).
Mesoamerica (n.): 1948, from meso- + America.
mesocracy (n.): "government by the middle classes," 1858, from meso- + -cracy. Related: Mesocratic (1857).
mesoderm (n.): 1858, from French mésoderme or German Mesoderm, literally "middle skin," coined by German physician Robert Remak (1815-1865) from meso- + Greek derma (see -derm).
mesolithic (adj.): 1866 in archaeology (somewhat earlier in geology); see meso- + lithic.
mesomorph (n.): 1940, from meso- + Greek morphe "form" (see Morpheus). Coined by W.H. Shelton; the reference is to the mesodermal layer of the embryo. Related: Mesomorphic (attested from 1923 in chemistry).
meson (n.): subatomic particle, 1939, from Greek mesos "middle" (see medial (adj.)) + subatomic particle suffix -on. Earlier mesotron (1938). So called for being intermediate in mass between protons and electrons.
Mesopotamia: ancient name for the land that lies between the Tigris and Euphrates rivers (in modern Iraq), from Greek mesopotamia (khora), literally "a country between two rivers," from fem. of mesopotamos, from mesos "middle" (see medial (adj.)) + potamos "river" (see potamo-).

In 19c. the word sometimes was used in the sense of "anything which gives irrational or inexplicable comfort to the hearer," based on the story of the old woman who told her pastor that she "found great support in that comfortable word Mesopotamia" ["Brewer's Dictionary of Phrase & Fable," 1870]. The place was called Mespot (1917) by British soldiers serving there in World War I. Related: Mesopotamian.
mesosphere (n.): 1950, from meso- + second element in atmosphere.
Mesozoic (adj.): 1840, from Greek mesos "middle" (see meso-) + zoe "life" (see zoo) + -ic. Name coined by British geologist John Phillips for the fossil era "between" the Paleozoic and the Cenozoic.
mesquite (n.): type of North American shrub of the pea family, 1759, from Mexican Spanish mezquite, from Nahuatl (Aztec) mizquitl "mesquite."
mess (n.): c.1300, "food for one meal, pottage," from Old French mes "portion of food, course at dinner," from Late Latin missus "course at dinner," literally "a placing, a putting (on a table, etc.)," from past participle of mittere "to put, place," in classical Latin "to send, let go" (see mission).

Meaning "communal eating place" (especially a military one) is first attested 1530s, from earlier sense of "company of persons eating together" (early 15c.), originally a group of four. Sense of "mixed food," especially for animals, (1738) led to contemptuous use for "jumble, mixed mass" (1828) and figurative sense of "state of confusion" (1834), as well as "condition of untidiness" (1851). General use for "a quantity" of anything is attested by 1830. Meaning "excrement" (of animals) is from 1903.
mess (v.): late 14c., "serve up in portions," from mess (n.). Meaning "take one's meals" is from 1701; that of "make a mess" is from 1853. Related: Messed; messing. To mess with "interfere, get involved" is from 1903; mess up "make a mistake, get in trouble" is from 1933 (earlier" make a mess of," 1909), both originally American English colloquial.
message (n.): c.1300, "communication transmitted via a messenger," from Old French message "message, news, tidings, embassy" (11c.), from Medieval Latin missaticum, from Latin missus "a sending away, sending, despatching; a throwing, hurling," noun use of past participle of mittere "to send" (see mission). The Latin word is glossed in Old English by ærende. Specific religious sense of "divinely inspired communication via a prophet" (1540s) led to transferred sense of "the broad meaning (of something)," first attested 1828. To get the message "understand" is from 1960.
message (v.): "to send messages," 1580s, from message (n.). Related: Messaged; messaging.
messaging (n.): 1865, verbal noun from message (v.).
Messalina: "scheming and licentious woman," 1887, in reference to Valeria Messalina, notorious third wife of Roman emperor Claudius.
messenger (n.): c.1200, messager, from Old French messagier "messenger, envoy, ambassador," from message (see message (n.)). With parasitic -n- inserted by c.1300 for no apparent reason except that people liked to say it that way (cf. passenger, harbinger, scavenger).
Messerschmitt (n.): type of German warplane, 1940, from name of Willy Messerschmitt (1898-1978), German aircraft designer. The surname is literally "cutler, knife-maker."
messiah (n.): c.1300, Messias, from Late Latin Messias, from Greek Messias, from Aramaic meshiha and Hebrew mashiah "the anointed" (of the Lord), from mashah "anoint." This is the word rendered in Septuagint as Greek Khristos (see Christ). In Old Testament prophetic writing, it was used of an expected deliverer of the Jewish nation. The modern English form represents an attempt to make the word look more Hebrew, and dates from the Geneva Bible (1560). Transferred sense of "an expected liberator or savior of a captive people" is attested from 1660s.
messianic (adj.): 1831, from Modern Latin messianicus, from Messias (see messiah).
Messier: in reference to a catalogue of about 100 nebulae, star clusters and galaxies begun in 1758 by French astronomer and comet-hunter Charles Messier (1730-1817), who at the time was looking for an expected return of Halley's comet and deceived by fuzzy objects that looked like distant comets in his telescope but turned out to not be.
What caused me to undertake the catalog was the nebula I discovered above the southern horn of Taurus on September 12, 1758, whilst observing the comet of that year. This nebula had such a resemblance to a comet in its form and brightness that I endeavored to find others, so that astronomers would no more confuse these same nebulae with comets just beginning to appear. [Messier, 1800]
The first version of the catalogue was published 1771, and the fuller version in 1781.
messmate (n.): 1746, from mess (n.) + mate (n.).
messrs: abbreviation of messieurs (1620s), which is the plural of French monsieur (see monsieur).
messuage (n.): legal term for "dwelling," late 14c., (late 13c. in Anglo-Latin), from Anglo-French messuage, which probably is a clerical error for mesnage (see menage). Originally the portion of land set aside for a dwelling-house and outbuildings, whether occupied by them or not; later chiefly in reference to the house and buildings and the attached land.
messy (adj.): 1843, "untidy," from mess (n.) + -y (2). Figurative use ("unethical") by 1924. Related: Messily; messiness.
mestizo (adj.): 1580s, from Spanish mestizo "of mixed European and Amerindian parentage," from Late Latin mixticius "mixed, mongrel," from Latin mixtus "mixed," past participle of miscere "to mix, mingle" (see mix (v.)). Fem. form mestiza is attested from 1580s.
Met (n.): 1879 as colloquial shortening of Metropolitan (n.) "member of the New York Metropolitan Base-Ball Club."
THE baseball season has opened, and along with the twittering of the birds, the budding of the trees, and the clattering of the truck, comes the news that the "Mets were beaten yesterday 17 to 5." It is an infallible sign of spring when the Mets are beaten 17 to 5, and we invariably put on our thinner clothing when we read that refreshing, though perennial news in the papers. ["Life," May 12, 1887]
Used variously to abbreviate other proper names beginning with Metropolitan, e.g. "Metropolitan Museum of Art" (N.Y.), by 1919; "Metropolitan Railway" (stock), by 1890; "Metropolitan Opera Company (N.Y.), by 1922. Related: Mets.
met (v.): past tense and past participle of meet (v.).