muslin (n.)youdaoicibaDictYouDict[muslin 词源字典]
c. 1600, "delicately woven cotton fabric," from French mousseline (17c.), from Italian mussolina, from Mussolo, Italian name of Mosul, city in northern Mesopotamia (modern Iraq) where muslin was made. Like many fabric names, it has changed meaning over the years, in this case from luxurious to commonplace. In 13c. French, mosulin meant "cloth of silk and gold." The meaning "everyday cotton fabric for shirts, bedding, etc." is first attested 1872 in American English.[muslin etymology, muslin origin, 英语词源]
muss (v.)youdaoicibaDictYouDict
"to make untidy," 1837, probably a variant of mess in its sense of "disorder." Earlier (1830) as a noun meaning "disturbance." Related: Mussed; mussing.
mussel (n.)youdaoicibaDictYouDict
Old English muscle, musscel "shellfish, mussel," from Late Latin muscula (source of Old French musle, Modern French moule, Middle Dutch mosscele, Dutch mossel, Old High German muscula, German Muschel), from Latin musculus "mussel," literally "little mouse," also "muscle;" like muscle, derived from mus "mouse" on the perceived similarity of size and shape. The modern spelling, distinguishing the word from muscle, first recorded c. 1600, not fully established until 1870s.
Mussulman (n.)youdaoicibaDictYouDict
"a Muslim," 1560s, from Turkish musulman, from Persian musulman (adj.), from Arabic muslim (see Muslim) + adjective suffix -an.
mussy (adj.)youdaoicibaDictYouDict
"rumpled," 1859, from muss + -y (2). Related: Mussiness.
must (v.)youdaoicibaDictYouDict
Old English moste, past tense of motan "have to, be able to," from Proto-Germanic *mot- "ability, leisure (to do something)" (cognates: Old Saxon motan "to be obliged to, have to," Old Frisian mota, Middle Low German moten, Dutch moeten, German müssen "to be obliged to," Gothic gamotan "to have room to, to be able to"), perhaps from PIE root *med- "to measure, to take appropriate measures" (see medical (adj.)). Used as present tense from c. 1300, from the custom of using past subjunctive as a moderate or polite form of the present.
must (n.1)youdaoicibaDictYouDict
"new wine," Old English must, from Latin mustum (also source of Old High German, German most, Old French moust, Modern French moût, Spanish, Italian mosto), short for vinum mustum "fresh wine," neuter of mustus "fresh, new, newborn," perhaps literally "wet," and from PIE *mus-to-, from root *meus- "damp" (see moss).
must (n.2)youdaoicibaDictYouDict
"mold," c. 1600, perhaps a back-formation of musty (q.v.).
must (n.3)youdaoicibaDictYouDict
"male elephant frenzy," 1871, from Urdu mast "intoxicated, in rut," from Persian mast, literally "intoxicated," related to Sanskrit matta- "drunk, intoxicated," past participle of madati "boils, bubbles, gets drunk," from PIE root *mad- "wet, moist" (see mast (n.2)).
must (n.4)youdaoicibaDictYouDict
"that which has to be done, seen, or experienced," 1892, from must (v.). As an adjective, "obligatory, indispensable," by 1912, from the noun; must-read is from 1959.
mustache (n.)youdaoicibaDictYouDict
1580s, from French moustache (15c.), from Italian mostaccio, from Medieval Greek moustakion, diminutive of Doric mystax (genitive mystakos) "upper lip, mustache," related to mastax "jaws, mouth," literally "that with which one chews," from PIE root *mendh- "to chew" (see mandible).

Borrowed earlier (1550s) as mostacchi, from the Italian word or its Spanish derivative mostacho. The plural form of this, mustachios, lingers in English. Slang shortening stache attested from 1985. Dutch slang has a useful noun, de befborstel, to refer to the mustache specifically as a tool for stimulating the clitoris; probably from beffen "to stimulate the clitoris with the tongue."
mustachioed (adj.)youdaoicibaDictYouDict
1817, from mustachio (1550s), from Spanish mostacho and directly from Italian mostaccio (see mustache). The noun was superseded by mustache, but the adjective has endured.
mustang (n.)youdaoicibaDictYouDict
"small, half-wild horse of the American prairie," 1808, from Mexican Spanish mestengo "animal that strays" (16c.), from Spanish mestengo "wild, stray, ownerless," literally "belonging to the mesta," an association of cattle ranchers who divided stray or unclaimed animals that got "mixed" with the herds, from Latin mixta "mixed," fem. past participle of miscere "to mix" (see mix (v.)).

Said to be influenced by the Spanish word mostrenco "straying, wild," which is probably from mostrar, from Latin monstrare "to show."
mustard (n.)youdaoicibaDictYouDict
late 13c. (late 12c. as a surname), from Old French mostarde "mustard, mustard plant" (Modern French moutarde), from moust "must," from Latin mustum "new wine" (see must (n.1)); so called because it was originally prepared by adding must to the ground seeds of the plant to make a paste. As a color name, it is attested from 1848.

Mustard gas, World War I poison (first used by the Germans at Ypres, 1917), so called for its color and smell and burning effect on eyes and lungs; chemical name is dichlordiethyl sulfide, it contains no mustard, and is an atomized liquid, not a gas. To cut the mustard (1907, usually in negative) is probably from slang mustard "genuine article, best thing" (1903) on notion of "that which enhances flavor."
I'm not headlined in the bills, but I'm the mustard in the salad dressing just the same. [O.Henry, "Cabbages and Kings," 1904]
mustee (n.)youdaoicibaDictYouDict
"octoroon, offspring of a white and a quadroon," also "half-caste," 1690s, a corruption of Spanish mestizo (q.v.).
mustelid (n.)youdaoicibaDictYouDict
1910, from Modern Latin Mustelidae, taken as a genus name by Linnaeus (1758), from Latin mustela "weasel," possibly related to mus "mouse" (see mouse (n.)). Tucker tentatively suggests *mus-ters-la "mouse harrier" and Klein notes that the weasel was identified in antiquity as "the catcher of mice."
musteline (adj.)youdaoicibaDictYouDict
"weasel-like; pertaining to weasels," 1650s, from Latin mustela (see mustelid) + -ine (1).
muster (v.)youdaoicibaDictYouDict
c. 1300, "to display, reveal, appear," from Old French mostrer "appear, show, reveal," also in a military sense (10c., Modern French montrer), from Latin monstrare "to show," from monstrum "omen, sign" (see monster). Meaning "to collect, assemble" is early 15c.; figurative use (of qualities, etc.) is from 1580s. To muster out "gather to be discharged from military service" is 1834, American English. To muster up in the figurative and transferred sense of "gather, summon, marshal" is from 1620s. Related: Mustered; mustering.
muster (n.)youdaoicibaDictYouDict
late 14c., "action of showing, manifestation," from Old French mostre "illustration, proof; examination, inspection" (13c., Modern French montre), literally "that which is shown," from mostrer (see muster (v.)). Meaning "act of gathering troops" is from c. 1400. To pass musters (1570s) originally meant "to undergo military review without censure."
mustn'tyoudaoicibaDictYouDict
by mid-18c., contraction of must not; see must (v).