Online Etymology Dictionary

mossy (adj.): 1560s, from moss + -y (2).
most (adj.): Old English mast "greatest number, amount, extent," earlier mæst, from Proto-Germanic *maistaz (cf. Old Saxon mest, Old Frisian mast, Old Norse mestr, Dutch meest, German meist, Gothic maists "most"), superlative form of Proto-Germanic *maiz, root of Old English ma, mara (see more). Used in Old English as superlative of micel "great, large" (see mickle). Vowel influenced by more. Original sense of "greatest" survives in phrase for the most part (c.1400). Slang meaning "the best, extremely good" is attested from 1953. Also used as an adverb in Old English. Phrase make the most of (something) is by 1520s. Related: Mostly. Double superlative mostest is 1885, from U.S. Southern and Black English.
Mosul: city in northern Iraq, from Arabic al-Mawsul, literally "the joined," a reference to the bridge and ford over the Tigris here.
mot (n.): "a witty saying," 1580s, from French mot (12c.) "remark, short speech," literally "word," cognate of Italian motto, from Latin mutum "grunt, murmur" (see mutter). Mot juste (1912) is French, literally "exact word," the precisely appropriate expression in some situation.
The mot juste is an expression which readers would like to buy of writers who use it, as one buys one's neighbour's bantam cock for the sake of hearing its voice no more. [Fowler]
mote (n.): "particle of dust," Old English mot, of unknown origin; perhaps related to Dutch mot "dust from turf, sawdust, grit," Norwegian mutt "speck, mote, splinter, chip." Many references are to Matt. vii:3.
motel (n.): 1925, coined from motor- + hotel. Originally a hotel for automobile travelers.
The Milestone Interstate Corporation ... proposes to build and operate a chain of motor hotels between San Diego and Seattle, the hotels to have the name 'Motel.' ["Hotel Monthly," March 1925]
motet (n.): "choral composition on a sacred text," late 14c., from Old French motet (13c.), diminutive of mot "word" (see mot).
moth (n.): Old English moððe (Northumbrian mohðe), common Germanic (cf. Old Norse motti, Middle Dutch motte, Dutch mot, German Motte "moth"), perhaps related to Old English maða "maggot," or from the root of midge (q.v.). Until 16c. used mostly of the larva and usually in reference to devouring clothes (cf. Matt. vi:20).
mothball (n.): also moth-ball, moth ball, "naphthalene ball stored among fabrics to keep off moths," 1891, from moth + ball (n.1).
mothball (v.): 1902 in a literal sense (to store away with mothballs), from mothball (n.); figurative sense from 1901.
mother (n.1): Old English modor "female parent," from Proto-Germanic *mothær (cf. Old Saxon modar, Old Frisian moder, Old Norse moðir, Danish moder, Dutch moeder, Old High German muoter, German Mutter), from PIE *mater- "mother" (cf. Latin mater, Old Irish mathir, Lithuanian mote, Sanskrit matar-, Greek meter, Old Church Slavonic mati), "[b]ased ultimately on the baby-talk form *mā- (2); with the kinship term suffix *-ter-" [Watkins]. Spelling with -th- dates from early 16c., though that pronunciation is probably older.

Mother nature first attested c.1600; mother earth is from 1580s. Mother tongue "one's native language" first attested late 14c. Mother of all ________ 1991, is Gulf War slang, from Saddam Hussein's use in reference to the coming battle; it is an Arabic idiom (as well as an English one), cf. Ayesha, second wife of Muhammad, known as Mother of Believers. Mother Carey's chickens is late 18c. sailors' nickname for storm petrels, or for snowflakes. Mother lode attested by c.1882, from mining [1849].
mother (v.): 1540s, "to be the mother of," from mother (n.1). Meaning "to take care of" is from 1863. Related: Mothered; mothering.
mother (n.2): "a thick substance concreting in liquors; the lees or scum concreted" [Johnson], probably from Middle Dutch modder "filth, dregs," from PIE *meu- (see mud).
Mother Goose: probably a translation of mid-17c. French contes de ma mère l'oye, which meant "fairy tales." The phrase appeared on the frontispiece of Charles Perrault's 1697 collection of eight fairy tales ("Contes du Temps Passé"), which was translated in English 1729 as "Mother Goose's Tales", and a very popular collection of traditional nursery rhymes published by John Newbery c.1765 was called "Mother Goose's Melody." Her own biographical story is no earlier than 1806.
Mother Hubbard: Old Mother Hubbard, nursery rhyme, was printed 1805, written by Sarah Catherine Martin (1768-1826) but based on earlier material of unknown origin (the name is attested from 1591).
mother of pearl (n.): c.1500, translating Medieval Latin mater perlarum, with the first element perhaps connected in popular imagination with obsolete mother (n.2) "dregs." Cf. Italian madreperla, French mère-perle, Dutch parelmoer, German Perlmutter, Danish perlemor.
mother-in-law (n.): mid-15c., "mother of one's spouse," from mother (n.1) + in-law. Also in early use, "stepmother." In British slang c.1884, mother-in-law was "a mixture of ales old and bitter."
motherfucker (n.): also mother-fucker, mother fucker, usually simply an intensive of fucker (see fuck), attested from 1956; implied in clipped form mother (with the context made clear) by 1928; motherfucking is from 1933.
motherhood (n.): 1590s, from mother (n.1) + -hood.
motherland (n.): 1711, from mother (n.1) + land (n.).
motherless (adj.): Old English moderleas; see mother (n.) + -less.
motherly (adj.): Old English modorlic "pertaining to a mother;" see mother (n.1) + -ly (1). Meaning "befitting a mother" is from mid-13c. Related: Motherliness.
Mothers' Day: the spelling used in the U.S. congressional resolution first recognizing it, May 9, 1908.
mothership (n.): also mother-ship, 1890, from mother (n.1) + ship (n.).
motif (n.): "theme, predominant feature," 1848, from French motif "dominant idea, theme" (see motive).
motile (adj.): "capable of movement," 1831, back-formation from motility.
motility (n.): "capacity of movement," 1827, from French motilité (1827), from Latin mot-, stem of movere "to move" (see move (v.)).
motion (n.): late 14c., "suggestion; process of moving," from Old French mocion "movement, motion; change, alteration" (13c.), from Latin motionem (nominative motio) "a moving, a motion; an emotion," from past participle stem of movere "to move" (see move (v.)). Motion picture attested from 1896.
motion (v.): late 15c., "to request, petition" (obsolete), from motion (n.). The sense in parliamentary procedure first recorded 1747; with meaning "to guide or direct by a sign, gesture, movement" it is attested from 1787. Related: Motioned; motioning.
motionless (adj.): 1590s, from motion (n.) + -less. Related: Motionlessly; motionlessness.
motivate (v.): 1863, "to stimulate toward action," from motive + -ate (2); perhaps modeled on French motiver or German motivieren. Related: Motivated; motivating.
motivation (n.): 1873, from motivate + -ion. Psychological use, "inner or social stimulus for an action," is from 1904.
motivational (adj.): 1931, from motivation + -al (1).
motivator (n.): 1917, agent noun in Latin form from motivate (v.).
motive (n.): mid-14c., "something brought forward," from Old French motif "will, drive, motivation," noun use of adjective, literally "moving," from Medieval Latin motivus "moving, impelling," from Latin motus "a moving, motion," past participle of movere "to move" (see move (v.)). Meaning "that which inwardly moves a person to behave a certain way" is from early 15c.
motive (adj.): late 14c., from Old French motif "moving" or directly from Medieval Latin motivus "moving, impelling," from past participle stem of movere "to move" (see move (v.)).
motiveless (adj.): 1817, from motive (n.) + -less.
motley (adj.): late 14c., "parti-colored" (originally of fabric), from Anglo-French motteley, probably from Old English mot "speck" (see mote). But Klein's sources say probably from Gaulish. "Diversified in color," especially of a fool's dress. Hence, allusively, "a fool" (1600). As a noun meaning "cloth of mixed color" from late 14c.
moto-: word-forming element meaning "motion, motor," from Latin motus, past participle of movere (see move (v.)).
motocross: also moto-cross, by 1956, from motorcycle + cross-country.
motor (n.): mid-15c., "controller, prime mover," from Latin motor, literally "mover," agent noun from past participle stem of movere "to move" (see move (v.)). From 15c. as "controller, prime mover" (in reference to God); sense of "agent or force that produces mechanical motion" is first recorded 1660s; that of "machine that supplies motive power" is from 1856. First record of slang motor-mouth "fast-talking person" is from 1970.
motor (v.): 1896, from motor (n.). Related: Motored; motoring.
motor-: element used extensively in 20c. word formation to indicate motorcar.
motor-boat (n.): also motorboat, 1902, from motor (n.) + boat (n.).
motorcade (n.): 1909, from motor- + suffix from cavalcade.
motorcar (n.): also motor-car, 1895 from motor (n.) + car.
motorcycle (n.): 1895, a hybrid from motor + -cycle, from bicycle. Motocycle also was used late 19c.
The horse follows the crooks of a country road, but then the training of the "motorcycle" (horrid name) will inevitably straighten out the crooks in the country road, and afford long ranges of straight tracks. [Payson Burleigh, "The Age of Steel," Oct. 12, 1895]
Related: Motorcyclist.
motorist (n.): "motor-car driver," 1896, from motor- + -ist. Earlier as a name for electric railway drivers (1889). Other early alternatives included motorneer.
"Motorer" we have given our reasons for rejecting, and there only remains "motorist" or a compound like "motor-man" or "motor-driver." Mr. C.P.G. Scott, the etymologist of the Century Dictionary, strongly favors "motor-man" or "motor-driver," though he would not object to "motorist" and prefers it above any other single word. ["Electric Power," October 1889]
motorize (v.): "to furnish with a motor or motors," 1901, from motor (n.) + -ize. Related: Motorized; motorizing; motorization.
motorway (n.): 1903, from motor- + way.