Online Etymology Dictionary

digest (v.): "assimilate food in bowels," c.1460 (digestion is attested from late 14c.), from L. digestus (see digest (n.)).
digit: late 14c., from L. digitus "finger or toe," related to dicere "tell, say, point out" (see diction). Numerical sense is because numerals under ten were counted on fingers. Digital (1650s) is first recorded 1945 in reference to computers, 1960 of recording or broadcasting.
digitalis: 1664, Mod.L. translation of Ger. fingerhut, the Ger. name of "foxglove," lit. "thimble." Named by Fuchs (1542).
dignity: early 13c., from O.Fr. dignete, from L. dignitatem (nom. dignitas) "worthiness," from dignus "worth (n.), worthy, proper, fitting" from PIE *dek-no-, from base *dek- "to take, accept" (see decent). Dignitary is first recorded 1670s.
digress: 1520s, from L. digress-, pp. stem of digredi "to go aside, depart" (see digression).
digression: late 14c., from L. digressionem, from digredi "to deviate," from dis- "apart, aside" + gradi "to step, go."
dike: O.E. dic "trench, ditch," from P.Gmc. *dik- (cf. O.N. diki, Du. dijk, Ger. Deich), from PIE base *dheigw- "to pierce, fasten" (cf. Skt. dehi- "wall," O.Pers. dida "wall, stronghold, fortress," Pers. diz). At first "an excavation," later (1487) applied to the resulting earth mound; a sense development paralleled by cognate forms in many other languages. This is the northern variant of the word, which in the south of England yielded ditch.
dilapidated: 1806, pp. adj. from dilapidate (1560s); see dilapidation.
dilapidation: c.1425, from L.L. dilapidationem, from L. dilapidare "pelt with stones, ruin, destroy," from dis- "asunder" + lapidare "throw stones at," from lapis (gen. lapidis) "stone." "Taken in Eng. in a more literal sense than was usual in Latin" [O.E.D.].
dilate: late 14c., from O.Fr. dilater, from L. dilatare "make wider, enlarge," from dis- "apart" + latus "wide" (see latitude).
dilatory: 1530s, from L. dilatorius, from dilator "procrastinator," from dilatus, serving as pp. of differe "delay" (see defer).
dildo: c.1593, perhaps a corruption of It. deletto "delight," or (less likely) of Eng. diddle (q.v.). "Curse Eunuke dilldo, senceless counterfet" ["Choise of Valentines or the Merie Ballad of Nash his Dildo," T. Nashe, c.1593]
dilemma: 1523, from L.L. dilemma, from Gk. dilemma "double proposition," a technical term in rhetoric, from di- "two" + lemma "premise, anything taken," from base *lab-. It should be used only of situations where someone is forced to choose between two alternatives, both unfavorable to him. But even logicians disagree on whether certain situations are dilemmas or mere syllogisms.
dilettante: 1733, borrowing of It. dilettante "lover of music or painting," from dilettare "to delight," from L. delectare (see delight). Originally without negative connotation, "devoted amateur," the pejorative sense emerged late 18c. by contrast with professional.
diligence: mid-14c., from O.Fr. diligence "attention, care," from L. diligentia "attentiveness, carefulness," from diligentem (nom. diligens) "attentive, assiduous, careful," originally prp. of diligere "value highly, love, choose," from dis- "apart" + legere "choose, gather" (see lecture). Sense evolved from "love" through "attentiveness" to "carefulness" to "steady effort."
diligent: mid-14c., from Fr. diligent (13c.), from L. diligentem "attentive, assiduous," originally prp. of diligere (see diligence). Related: Diligently.
dill: O.E. dile "dill, anise," a W.Gmc. word of unknown origin.
dilly: "delightful or excellent person or thing" (often used ironically), 1935, from an earlier adj. (1909), perhaps from the first syllable of delightful or delicious, or related to the nursery word for "duck." Dilly was also slang for a stagecoach (1818), from Fr. carrosse de diligence. The noun is 1935. Dilly-dally is from 1741, a reduplication of dally.
dilute: c.1555, from L. dilutus, pp. of diluere "dissolve, wash away, dilute," from dis- "apart" + -luere, comb. form of lavere "to wash" (see lave).
dim: O.E. dimm "dark, gloomy, obscure," from P.Gmc. *dimbaz. Not known outside Gmc. The verb was also in O.E. Slang sense of "stupid" is from 1892; dimwit first recorded 1917.
dim sum: 1948, from Cantonese dim sam (Chinese dianxin) "appetizer," said to mean lit. "touch the heart."
dime: chosen 1786 as name for U.S. 10 cent coin, from dime "a tenth, tithe" (late 14c.), from O.Fr. disme, from L. decima (pars) "tenth (part)," from decem "ten" (see ten). The verb meaning "to inform" (on someone) is 1960s, from the then-cost of a pay phone call. A dime a dozen "almost worthless" first recorded 1930. Phrase stop on a dime attested by 1954 (a dime being the physically smallest unit of U.S. currency).
dimension: 1413, from L. dimensionem (nom. dimensio), from stem of dimetri "to measure out," from dis- + metri "to measure."
diminish: 1417, from merger of two obsolete verbs, diminue and minish. Diminue is from O.Fr. diminuer "make small," from L. diminuere "break into small pieces," variant of deminuere "lessen, diminish," from de- "completely" + minuere "make small," from root of minus (see minus). Minish is from O.Fr. menuisier, from L. minuere.
diminutive: late 14c., from O.Fr. diminutif (fem. diminutive), from L. diminutivum, from deminuere (see diminish).
dimple: c.1400, probably existed in O.E. as a word meaning "pothole," perhaps ult. from P.Gmc. *dumpilaz, which has yielded words in other languages meaning "small pit, little pool."
din: O.E. dyne (n.), dynian (v.), from P.Gmc. *duniz, from PIE base *dhun- "loud noise" (cf. Skt. dhuni "roaring, a torrent").
dine: c.1300, from O.Fr. disner, originally "take the first meal of the day," from stem of Gallo-Romance *desjunare "to break one's fast," from L. dis- "undo" + L.L. jejunare "to fast," from L. jejunus "fasting, hungry." Diner "railway car for eating" is 1890, Amer.Eng. Dinette is 1930, with false Fr. ending.
ding: 1819, "to sound as metal when struck," possibly abstracted from ding-dong (1659), of imitative origin. The verb meaning "to deal heavy blows" is c.1300, probably from O.N. dengja "to hammer." Meaning "dent" is 1960s. Dinger "something superlative" (e.g. humdinger) is from 1809, Amer.Eng. Ding-a-ling "one who is crazy" is 1935, from notion of hearing bells in the head.
dingbat: 1838, Amer.Eng., "some kind of alcoholic drink," of unknown origin. One of that class of words (e.g. dingus, doohickey, gadget, gizmo, thingumabob) which are conjured up to supply names for items whose proper names are unknown or not recollected. Used at various periods for "money," "a professional tramp," "a muffin," "a typographical ornament," "male genitalia," "a Chinese," "an Italian," "a woman who is neither your sister nor your mother," and "a foolish person in authority." Popularized in sense of "foolish person" by TV show "All in the Family" (1971), though this usage dates from 1905.
dinghy: 1810, from Hindi dingi "small boat," perhaps from Skt. drona-m "wooden trough," related to dru-s "wood, tree."
dingle: "deep dell or hollow, usually wooded," c.1240, of unknown origin; a dialectal word until it entered literary use 17c.
dingo: 1789, Native Australian name, from Dharruk (language formerly spoken in the area of Sydney) /din-go/ "tame dog," though the English used it to describe wild Australian dogs. Bushmen continue to call the animal by the Dharruk term /warrigal/ "wild dog."
dingus: "any unspecified or unspecifiable object; something one does not know the name of or does not wish to name," 1876, U.S. slang, from Du. dinges, lit. "thing" (see thing).
dingy: 1736, Kentish dialect, "dirty," of uncertain origin, but probably related to dung.
dinkum: 1888, "hard work," Australian slang, of unknown origin, perhaps connected to Lincolnshire dialect. Meaning "honest, genuine" is attested from 1894.
dinky: 1788 "neat, trim, dainty, small," from Scot. dialect dink "finely dressed, trim" (1508), of unknown origin. Modern sense is 1850s.
dinner: c.1300, from O.Fr. disner, originally "breakfast," later "lunch," noun use of infinitive disner (see dine). Always used in Eng. for the main meal of the day; shift from midday to evening began with the fashionable classes. Childish reduplication din-din is attested from 1905.
dinosaur: 1841, coined by Sir Richard Owen, from Gk. deinos "terrible" + sauros "lizard," of unknown origin. Fig. sense of "person or institution not adapting to change" is from 1952.
dint: O.E. dynt "blow dealt in fighting" (especially by a sword), from P.Gmc. *duntiz. Phrase by dint of ... "by force of, by means of," is early 14c.
diocese: early 14c., from O.Fr. diocese, from L.L. diocesis "a governor's jurisdiction," later, "a bishop's jurisdiction," from Gk. diokesis "province," originally "economy, housekeeping," from diokein "manage a house," from dia- "thoroughly" + oikos "house" (see villa).
Dionysian: c.1610, from Gk. Dionysos, god of wine and revelry, identified with Roman Bacchus.
diorama: 1823 as a type of picture-viewing device, from Fr. (1822), from Gk. di- "through" + orama "that which is seen, a sight." Invented by Daguerre and Bouton, first exhibited in London Sept. 29, 1823. Meaning "small-scale replica of a scene, etc." is from 1902.
dioxin: 1919, from dioxy- + chemical suffix -in. All the compounds in the group are characterized by two oxygen atoms.
dip: O.E. dyppan "immerse, baptize by immersion," from P.Gmc. *dupjanan, related to diepan "immerse, dip." Sense of "downward slope" is 1708. Meaning "sweet sauce for pudding, etc." first recorded 1825. Dipper, the popular U.S. name for the asterism known in Britain as The Plough or Charles' Wain, is attested from 1842.
diphtheria: coined 1857 in Fr. by physician Pierre Bretonneau from Gk. diphthera "hide, leather," of unknown origin; the disease so called for the tough membrane that forms in the throat. Formerly known in England as the Boulogne sore throat, since it spread from France.
diphthong: 1483, from M.Fr., from L.L., from Gk. diphthongos, from di- "double" + phthongos "sound, voice," related to phthengesthai "utter, speak loudly."
diplodocus: 1884, coined in Mod.L. by O.C. Marsh (1878) from Gk. diploos "double" + dokos "a beam."
diploma: 1640s, from L. diploma, from Gk. diploma "license, chart," originally "paper folded double," from diploun "to double, fold over," from diplos "double." Specific academic sense is 1680s in English.
diplomacy: 1796, from Fr. diplomatie, formed from diplomate "diplomat" (on model of aristocratie from aristocrate), from L. adj. diplomaticos, from diploma (gen. diplomatis) "official document conferring a privilege" (see diploma; for sense evolution, see diplomatic). The English use of diplomat dates from 1813.