Online Etymology Dictionary

dutiful (adj.): 1550s, from duty + -ful. Related: Dutifully.
duty (n.): late 13c., from Anglo-French duete, from Old French deu "due, owed; proper, just," from Vulgar Latin *debutus, from Latin debitus, past participle of debere "to owe" (see debt). Related: Duties. The sense of "tax or fee on imports, exports, etc." is from late 15c.; duty-free as a noun is attested from 1958.
duvet (n.): 1758, from French duvet "down," earlier dumet, diminutive of dum "down."
DVD: 1995, initialism (acronym) from Digital Video Disc, later changed to Digital Versatile Disc.
Earlier this year, electronics giant Toshiba positioned the first DVD players available in the U.S. as a home entertainment unit (retail price $600). ["Black Enterprise" magazine, June 1997]
dwarf (n.): Old English dweorh, dweorg (West Saxon), duerg (Mercian), "very short human being," from Proto-Germanic *dweraz (source also of Old Frisian dwerch, Old Saxon dwerg, Old High German twerg, German Zwerg, Old Norse dvergr), perhaps from PIE *dhwergwhos "something tiny," but with no established cognates outside Germanic. The mythological sense is 1770, from German (it seems never to have developed independently in English).
Whilst in this and other ways the dwarfs do at times have dealings with mankind, yet on the whole they seem to shrink from man; they give the impression of a downtrodden afflicted race, which is on the point of abandoning its ancient home to new and more powerful invaders. There is stamped on their character something shy and something heathenish, which estranges them from intercourse with christians. They chafe at human faithlessness, which no doubt would primarily mean the apostacy from heathenism. In the poems of the Mid. Ages, Laurin is expressly set before us as a heathen. It goes sorely against the dwarfs to see churches built, bell-ringing ... disturbs their ancient privacy; they also hate the clearing of forests, agriculture, new fangled pounding-machinery for ore. ["Teutonic Mythology," Jacob Grimm, transl. Stallybrass, 1883]
The shift of the Old English guttural at the end of the word to modern -f is typical (compare enough, draft). Old English plural dweorgas became Middle English dwarrows, later leveled down to dwarfs. The use of dwarves for the legendary race was popularized by J.R.R. Tolkien. As an adjective, from 1590s.
dwarf (v.): "to render dwarfish," 1620s, from dwarf (n.); sense of "to cause to look small" is from 1850. Related: Dwarfed; dwarfing.
dwarfish (adj.): 1560s, from dwarf (n.) + -ish. Related: Dwarfishly; dwarfishness.
dweeb (n.): 1968, U.S. college student slang, probably a variant of feeb "feeble or feeble-minded person."
dwell (v.): Old English dwellan "to mislead, deceive," originally "to make a fool of, lead astray," from Proto-Germanic *dwelan "to go or lead astray" (source also of Old Norse dvöl "delay," dvali "sleep;" Middle Dutch dwellen "to stun, make giddy, perplex;" Old High German twellen "to hinder, delay;" Danish dvale "trance, stupor," dvaelbær "narcotic berry," source of Middle English dwale "nightshade"), from PIE *dhwel-, extended form of root *dheu- (1) "dust, cloud, vapor, smoke" (and related notions of "defective perception or wits").

Related to Old English gedweola "error, heresy, madness." Sense shifted in Middle English through "hinder, delay," to "linger" (c. 1200, as still in phrase to dwell upon), to "make a home" (mid-13c.). Related: Dwelled; dwelt; dwells.
dweller (n.): late 14c., agent noun from dwell (v.).
dwelling (n.): "place of residence," mid-14c., verbal noun from dwell (v.).
dwindle (v.): 1590s, apparently diminutive and frequentative of Middle English dwinen "waste away, fade, vanish," from Old English dwinan, from Proto-Germanic *dwinan (source also of Dutch dwijnen "to vanish," Old Norse dvina, Danish tvine, Low German dwinen), from PIE *dheu- (3) "to die" (see die (v.)). Related: Dwindled; dwindling.
dyad (n.): 1670s, from Latin dyad-, stem of dyas, from Greek dyas "the number two, a group of two," from duo "two" (see two). Specific sense in chemistry ("a bivalent element") is by 1865; also used in biology, poetics, mathematics. Related: Dyadic.
dybbuk (n.): "malevolent spirit of a dead person possessing the body of a living one," 1903, from Jewish folklore, from Hebrew dibbuk, from dabak "to cling, cleave to."
dye (n.): Old English deah, deag "a color, hue, tinge," perhaps related to deagol "secret, hidden, dark, obscure," from Proto-Germanic *daugilaz (source also of Old Saxon dogol "secret," Old High German tougal "dark, hidden, secret").
dye (v.): Old English deagian "to dye," from the source of dye (n.). Spelling distinction between dye and die was not firm till 19c. "Johnson in his Dictionary, spelled them both die, while Addison, his near contemporary, spelled both dye" [Barnhart]. Related: dyed. For dyed in the wool (or grain) see wool (n.).
dyeing: c. 1400, verbal noun and past participle adjective from dye (v.).
dyer (n.): late 14c. (late 13c. as a surname), agent noun from dye (v.).
dying: late 13c., "death," verbal noun from die (v.). From mid-15c. as a past participle adjective, "in the process of becoming dead."
dyke (n.): 1931, American English, perhaps a shortening of morphadike, dialectal garbling of hermaphrodite; but bulldyker "engage in lesbian activities" is attested from 1921, and a source from 1896 lists dyke as slang for "the vulva."
[T]he word appears first in the long forms, bulldiker and bulldyking, both used in the 1920s by American blacks. No African antecedents have been found for the term, however, which leads to the possibility that this is basically just another backcountry, barnyard word, perhaps a combination of BULL and DICK. [Rawson]
dynamic (adj.): 1817 as a term in philosophy; 1827 in the sense "pertaining to force producing motion" (the opposite of static), from French dynamique introduced by German mathematician Gottfried Leibnitz (1646-1716) in 1691 from Greek dynamikos "powerful," from dynamis "power," from dynasthai "to be able, to have power, be strong enough," which is of unknown origin. The figurative sense of "active, potent, energetic" is from 1856 (in Emerson). Related: Dynamically.
dynamic (n.): "energetic force; motive force," 1894, from dynamic (adj.).
dynamics (n.): as a branch of physics, 1789, from dynamic (adj.); also see -ics.
dynamism (n.): 1831, "dynamic energy, force, drive," from Greek dynamis "power, might, strength" (see dynamic (adj.)) + -ism. As a philosophical system, from 1857.
dynamite (n.): 1867, from Swedish dynamit, coined 1867 by its inventor, Swedish chemist Alfred Nobel (1833-1896), from Greek dynamis "power" (see dynamic (adj.)) + -ite (2). Figurative sense of "something potentially dangerous" is from 1922. Positive sense of "dynamic and excellent" by mid-1960s, perhaps originally African-American vernacular.
dynamite (v.): 1881, from dynamite (n.). Related: Dynamited; dynamiting.
dynamo (n.): 1882, short for dynamo-machine, from German dynamoelektrischemaschine "dynamo-electric machine," coined 1867 by its inventor, German electrical engineer Werner Siemans (1816-1892), from Greek dynamis "power."
dynast (n.): "hereditary ruler," 1630s, from Late Latin dynastes, from Greek dynastes (see dynasty).
dynastic (adj.): 1800; see dynasty + -ic.
dynasty (n.): mid-15c. (earlier dynastia, late 14c.), from Middle French dynastie and directly from Late Latin dynastia, from Greek dynasteia "power, lordship, sovereignty," from dynastes "ruler, chief," from dynasthai "have power."
dyne (n.): metric unit of force, 1873, from German use of Greek dynamis "power" (see dynamic (adj.)); perhaps also influenced by French dyne, which had been proposed c. 1842 as a unit of force in a different sense.
dys-: word-forming element meaning "bad, ill, abnormal," from Greek dys-, inseparable prefix "destroying the good sense of a word or increasing its bad sense" [Liddell & Scott], "bad, hard, unlucky," from PIE root (and prefix) *dus- "bad, ill, evil" (source also of Sanskrit dus-, Old Persian duš- "ill," Old English to-, Old High German zur-, Gothic tuz- "un-"), a derivative of the root *deu- (1) "to lack, be wanting" (source of Greek dein "to lack, want").

Very productive in ancient Greek, where it could attach even to proper names (such as dysparis "unhappy Paris"); its entries take up nine columns in Liddell and Scott. Among the words formed from it were some English might covet: dysouristos "fatally favorable, driven by a too-favorable wind;" dysadelphos "unhappy in one's brothers;" dysagres "unlucky in fishing;" dysantiblepos "hard to look in the face."
dysentery (n.): late 14c., dissenterie, from Old French disentere (13c.), from Latin dysenteria, from Greek dysenteria, coined by Hippocrates, from dys- "bad, abnormal, difficult" (see dys-) + entera "intestines, bowels" (see inter-). Related: Dysenteric.
dysfunction (n.): 1916, from dys- "bad, abnormal, difficult" + function (n.).
dysfunctional (adj.): 1917, from dysfunction + -al (1). Related: Dysfunctionally.
dyslexia (n.): c. 1887, from German dyslexie (1883), from Greek dys- "bad, abnormal, difficult" (see dys-) + lexis "word," from legein "speak" (see lecture (n.)) + abstract noun ending -ia. Dyslexic (n.) is first recorded 1961; dyslectic (adj.) from 1964.
dyspepsia (n.): 1706, from Late Latin dyspepsia or a back-formation from dyspeptic (q.v.). Its opposite is eupepsia.
dyspeptic (adj.): 1690s, from Greek dyspeptos "hard to digest," from dys- "bad" (see dys-) + peptos "digested," from peptein "digest" (see cook (n.)).
dysphemism (n.): 1884, "substitution of a vulgar or derogatory word or expression for a dignified or normal one," from Greek dys- "bad, abnormal, difficult" (see dys-) + pheme "speech, voice, utterance, a speaking," from phanai "speak" (see fame (n.); Greek dysphemia meant "ill language, words of ill omen"). The opposite of euphemism. Rediscovered 1933 from French formation dysphémisme (1927, Carnoy).
The French psychologist Albert J. Carnoy gave an extensive definition in his study Le Science du Mot, which in translation runs: "Dysphemism is unpitying, brutal, mocking. It is also a reaction against pedantry, rigidity and pretentiousness, but also against nobility and dignity in language" (1927, xxii, 351). [Geoffrey L. Hughes, "An Encyclopedia of Swearing," 2006]
dysplasia (n.): 1935, Modern Latin, from dys- + -plasia, from Greek plasis "molding, conformation," from plassein (see plasma) + abstract noun ending -ia.
dysprosium (n.): element, obtained 1906 from an earth discovered in 1886, the last to be extracted from the complex earth called yttria, and named dysprosia in reference to the difficulty of obtaining it, from Greek dysprositos "hard to get at, difficult of access," from dys- "bad" (see dys-) + prositos "approachable." With metallic element suffix -ium.
dystopia (n.): "imaginary bad place," 1868, apparently coined by J.S. Mill ("Hansard Commons"), from Greek dys- "bad, abnormal, difficult" (see dys-) + utopia. Related: Dystopian.
dystrophy (n.): also distrophy, "defective nutrition," 1858, from Modern Latin dystrophia, distrophia, from Greek dys- "hard, bad, ill" (see dys-) + trophe "nourishment" (see -trophy). Related: Dystrophic.