Online Etymology Dictionary

maw (n.): Old English maga "stomach" (of men and animals; in Modern English only of animals unless insultingly), from Proto-Germanic *magon "bag, stomach" (cf. Old Frisian maga, Old Norse magi, Danish mave, Middle Dutch maghe, Dutch maag, Old High German mago, German Magen "stomach"), from PIE *mak- "leather bag" (cf. Welsh megin "bellows," Lithuanian makas, Old Church Slavonic mošina "bag, pouch"). Meaning "throat, gullet" is from 1520s. Metaphoric of voracity from late 14c.
mawkish (adj.): 1660s, "sickly, nauseated," from Middle English mawke "maggot" (see maggot). Sense of "sickly sentimental" is first recorded 1702. Related: Mawkishly; mawkishness.
mawworm (n.): "worm infesting the stomach," c.1600, from maw (n.) + worm (n).
max (v.): "to reach the maximum level," by 1986, colloquial, from maximize or related words. Related: Maxed; maxing.
maxi-: word-forming element meaning "maximum, very large, very long," from comb. form of maximum.
maxilla (n.): "jaw, jawbone," 1670s, from Latin maxilla "upper jaw," diminutive of mala "jaw, cheekbone." "Maxilla stands to mala as axilla, 'armpit,' stands to ala 'wing'" [Klein]. Related: Maxillar; maxilliform.
maxillary (adj.): 1620s, from Latin maxilla (see maxilla) + -ary.
maxim (n.): "precept, principle," early 15c., from Middle French maxime, from Late Latin maxima, shortened from phrases such as maxima propositio, maxima sententarium "axiom," literally "greatest premise, greatest among propositions" (one which is general and absolute), from fem. of maximus "greatest" (see maximum).
Maxim: single-barreled water-cooled machine gun, 1885, named for inventor, U.S.-born British engineer Sir Hiram S. Maxim (1840-1916).
maximal (adj.): 1872, from Latin maximus (see maximum (n.)) + -al (1). Related: Maximally.
maximalist (n.): "extreme radical in the Russian Socialist Revolutionary Party," early 20c., from maximal + -ist; denoting "one who insists on all his demands." Related: Maximalism.
Maximilian: masc. proper name, from Latin Maximus and Aemilianus, both proper names. According to Camden, Holy Roman Emperor Frederick III (1415-1493) coined the name and gave it to his son in hopes the boy would grow up to have the virtues of Fabius Maximus and Scipio Aemilianus.
maximise (v.): chiefly British English spelling of maximize. For suffix, see -ize. Related: Maximised; maximising.
maximization (n.): 1802, noun of action from maximize.
maximize (v.): 1802, formed in English from maximum + -ize; first attested in Bentham, who used it often. Related: Maximized; maximizing.
maximum (n.): 1740, from French maximum and directly from Latin maximum (plural maxima), neuter of maximus "greatest," which is superlative of magnus "great, large" (see magnum).
maximum (adj.): 1834, from maximum (n.).
may (v.1): Old English mæg "am able" (infinitive magan, past tense meahte, mihte), from Proto-Germanic root *mag-, infinitive *maganan (Old Frisian mei/muga/machte "have power, may;" Old Saxon mag/mugan/mahte; Middle Dutch mach/moghen/mohte; Dutch mag/mogen/mocht; Old High German mag/magan/mahta; German mag/mögen/mochte; Old Norse ma/mega/matte; Gothic mag/magan/mahte "to be able"), from PIE *magh- (1) "to be able, have power" (cf. Greek mekhos, makhos "means, instrument," Old Church Slavonic mogo "to be able," mosti "power, force," Sanskrit mahan "great"). Also used in Old English as a "auxiliary of prediction."
May: fifth month, early 12c., from Old French mai and directly from Latin Majus, Maius mensis "month of May," possibly from Maja, Maia, a Roman earth goddess (wife of Vulcan) whose name is of unknown origin; possibly from PIE *mag-ya "she who is great," fem. suffixed form of root *meg- "great" (cognate with Latin magnus). Replaced Old English þrimilce, month in which cows can be milked three times a day. May marriages have been considered unlucky at least since Ovid's day. May-apple attested from 1733, American English.
may (v.2): "to take part in May Day festivities," late 15c., from May. Related: Mayed; maying.
May Day: "first of May," mid-15c. Accounts of merrymaking on this date are attested from mid-13c. Synonymous with "communist procession" from at least 1906. The May Queen seems to be a Victorian re-invented tradition.
Maya: 1822, from the native name. Related: Mayan (1831).
maybe (adv.): early 15c., from (it) may be; see may (v.1) + be (v.). Still sometimes written as two words early 19c.
mayday: "distress call," 1923, apparently an Englished spelling of French m'aider, shortening of venez m'aider "come help me!" But possibly a random coinage with coincidental resemblance:
"May Day" Is Airplane SOS
ENGLISH aviators who use radio telephone transmitting sets on their planes, instead of telegraph sets, have been puzzling over the problem of choosing a distress call for transmission by voice. The letters SOS wouldn't do, and just plain "help!" was not liked, and so "May Day" was chosen. This was thought particularly fitting since it sounds very much like the French m'aidez, which means "help me." ["The Wireless Age," June 1923]
Mayfair: fashionable district of London, developed 18c., built on Brook fields, where an annual May fair had been held 17c.
mayflower (n.): by 1620s; from May + flower (n.). Used locally for the cowslip, the lady's smock, and other plants that bloom in May.
mayhap: 1530s, from phrase (it) may hap.
mayhem (n.): late 15c., from Anglo-French maihem (13c.), from Old French mahaigne "injury, wrong, a hurt, harm, damage;" related to mahaignier "to injure, wound, mutilate, cripple" (see maim). Originally, in law, the crime of maiming a person "to make him less able to defend himself or annoy his adversary" [OED].
mayo (n.): shortened form of mayonnaise, first attested c.1930.
mayonnaise (n.): sauce made from egg yolks, oil, and vinegar, 1815, from French sauce mayonnaise (1806), said by French sources to be corrupted from mahonnaise and to have been named in recognition of Mahon, seaport capital of island of Minorca, captured by France 1756 after the defeat of the British defending fleet in the Seven Years' War; the sauce having been introduced either in commemoration of the victory, which was led by Armand de Vignerot du Plessis, duc de Richelieu (1696–1788), or because it was brought to France from there by him. But unless there is a gap in the record, the late date of appearance of the word make this seem doubtful.
mayor (n.): c.1300, from Old French maire "head of a city or town government" (13c.), originally "greater, superior" (adj.), from Latin maior, major, comparative of magnus "great" (see magnum).
mayoral (adj.): 1690s, from mayor + -al (1).
mayoralty (n.): late 14c., mairaltee "office of a mayor" (mid-15c. as "tenure of a mayor"), from Middle French mairalté, from maire (see mayor) + -alte, as in principalte, reformed in English as -alty.
mayorship (n.): late 15c., from mayor + -ship.
maypole (n.): "high striped pole decorated with flowers and ribbons for May Day merrymakers to dance around," attested from 1550s but certainly much older, as the first mention of it is in an ordinance banning them, and there are references to such erections, though not by this name, from a mid-14c. Welsh poem. See May Day.
maze (n.): c.1300, "delusion, bewilderment" (also as a verb, "stupefy, daze"), possibly from Old English *mæs, which is suggested by the compound amasod "amazed" and verb amasian "to confound, confuse" (see amaze). Perhaps related to Norwegian dialectal mas "exhausting labor," Swedish masa "to be slow or sluggish." Meaning "labyrinth" first recorded late 14c.
mazel tov: 1862, from modern Hebrew mazzal tob "good luck," from Hebrew mazzaloth (plural) "constellations."
mazuma (n.): slang for "money," 1894, from Yiddish, from Mishnaic Hebrew mezumman "designated, fixed, appointed," used in Medieval Hebrew in sense of "cash" (cf. slang the needful "money"), from Akkad. simanu "appointed time." It figured in "People v. Stokes," case argued before Supreme Court of California (1894), which cites newspaper coverage of an earlier trial mentioning "Colonel Mazuma":
It appears that the term "Colonel Mazuma" not only does not indicate some gentleman with a military title, but it does not even refer to a person at all. We fail to find the term mentioned by our lexicographers, but understand it to be a modern provincialism, probably emanating from the daily press, and used when referring to the corrupt application of money in the accomplishment of certain ends. If these jurors understood this term with the signification thus attached to it, it of itself furnished ample material to demand a retrial of the case. ["Pacific Reporter," vol. 37]
mazurka (n.): lively dance, also mazourka, 1818, from Russian mazurka, from Polish mazurek "dance of the Mazur," a reference to inhabitants of Mazowsze (Medieval Latin Mazovia), ancient region in central Poland. The Polish accusative in tanczyc mazurka "to dance the mazurek" was interpreted in Russian as a feminine affix, hence the -ka ending.
mazy (adj.): 1570s, from maze (n.) + -y (2).
McCarthyism: 1950, with -ism + name of U.S. Sen. Joseph R. McCarthy (1908-1957), leader of U.S. anti-Communist agitation. The term is said to have been coined by "Washington Post" political cartoonist Herbert Block ("Herblock"). The surname is from Irish Mac Carthaigh "son of Carthach" (Welsh Caradawc), an ancient Celtic name, also known in its Latinized form, Caractacus (last of the British leaders to resist Rome, captured 51 C.E.)
McConnell: Irish surname, from Irish mac "son of" + Conall, from Celt. kunovalos "high-powerful."
McCoy: as in the real McCoy, 1881, said to be from Scottish the real Mackay (1883), of uncertain origin, though there are many candidates, including whiskey distilled by A. and M. Mackay of Glasgow (the phrase the real McCoy became popular during Prohibition to describe liquor); Charles S. "Kid" McCoy (1872-1940), former welterweight boxing champ; and a claimant for chief of the northern branch of the clan Mackay.
"By jingo! yes; so it will be. It's the 'real McCoy,' as Jim Hicks says. Nobody but a devil can find us there." [James S. Bond, "The Rise and Fall of the Union Club," Yorkville, Canada, 1881]
McFarland: Irish surname, from Gaelic Mac Pharlain "son of Parlan," from Old Irish Parthalon "Bartholomew."
McGuffey's: children's reader, first published 1836, created by Ohio educator and linguist William Holmes McGuffey (1800-1873).
McIntosh: kind of red apples, 1874, from John McIntosh (b.1777), Ontario farmer who found them in 1796 while clearing woodland on his farm and began to cultivate them. The surname is Gaelic Mac an toisich "son of the chieftain."
McMillan: Irish surname, from Gaelic Mac Mhaolain "son of the tonsured one."
McQueen: Irish surname, from Gaelic Mac Shuibhne "son of Suibhne," literally "pleasant."
me (pron.): Old English me (dative), me, mec (accusative); oblique cases of I, from Proto-Germanic *meke (accusative), *mes (dative), cf. Old Frisian mi/mir, Old Saxon mi, Middle Dutch mi, Dutch mij, Old High German mih/mir, German mich/mir, Old Norse mik/mer, Gothic mik/mis; from PIE root *me-, oblique form of the personal pronoun of the first person singular (nominative *eg; see I); cf. Sanskrit, Avestan mam, Greek eme, Latin me, mihi, Old Irish me, Welsh mi "me," Old Church Slavonic me, Hittite ammuk.

Erroneous or vulgar use for nominative (e.g. it is me) attested from c.1500. Dative preserved in obsolete meseems, methinks and expressions such as sing me a song ("dative of interest"). Reflexively, "myself, for myself, to myself" from late Old English.
mea culpa: Latin, literally "I am to blame," a phrase from the prayer of confession in the Latin liturgy.