Online Etymology Dictionary

dice: c.1330, des, dys, pl. of dy (see die (n.)), altered 14c. to dyse, dyce, and 15c. to dice. "As in pence, the plural s retains its original breath sound, probably because these words were not felt as ordinary plurals, but as collective words" [OED]. Sometimes used as sing. 1400-1700. The v. "to cut into cubes" is first recorded c.1390. Dicey "doubtful, difficult" is RAF slang from the 1940s.
dichotomy: 1610, from Gk. dichotomia "a cutting in half," from dicha "in two" + temnein "to cut" (see tome).
dick: "fellow, lad, man," 1553, rhyming nickname for Rick, short for Richard, one of the commonest Eng. names, it has long been a synonym for "fellow," and so most of the slang senses are probably very old, but naturally hard to find in the surviving records. The meaning "penis" is attested from 1891 in British army slang; dickhead "stupid person" is from 1969. Meaning "detective" is recorded from 1908, perhaps as a shortened variant of detective. The Dick Whittington story is an old one, told under other names throughout Europe, of a poor boy who sends a cat he had bought for a penny as his stake in a trading voyage; the captain sells it on his behalf for a fortune to a foreign king whose palace is overrun by rats. The hero devotes part of his windfall to charity, which may be why the legend attached in England since 16c. to Sir Richard Whittington (d.1423), three times Lord Mayor of London, who died childless and devoted large sums in his will to churches, almshouses, and St. Bartholomew's Hospital.
dickens: exclamation, 1598, probably altered from Dickon, nickname for Richard and source of the surnames Dickens and Dickenson, but exact derivation and meaning are unknown.
dicker (v.): "haggle, bargain in a petty way," 1802, Amer.Eng., perhaps from dicker (n.) "a unit or package of tens," especially hides (attested from c.1275), probably from L. decuria "parcel of ten" (supposedly a unit of barter on the Roman frontier), from decem "ten."
dicky: "detached shirt front," 1811; "a small bird," 1851; dim. of dick, but the applications are obscure in both cases.
dictate (v.): 1592, "to practice dictation," from L. dictatus, pp. of dictare "say often, prescribe," freq. of dicere "tell, say" (see diction). Sense of "command" is 1621. The noun is from 1594. A dictator (1387) was a judge in the Roman republic temporarily invested with absolute power. Dictaphone is from 1907, a proprietary name (Columbia Phonograph Co.). Dictograph was patented 1907 in U.S. by K.M. Turner and W. Donnan.
diction: 1542, from L.L. dictionem (nom. dictio), from L. "a saying, expression, word," from dic-, stem of dicere "speak, tell, say," related to dicare "proclaim, dedicate," from PIE base *deik- "to point out" (cf. Skt. dic- "point out, show," Gk. deiknynai "to prove," O.H.G. zeigon, Ger. zeigen "to show," O.E. teon "to accuse," tæcan "to teach").
dictionary: 1526, from M.L. dictionarium "collection of words and phrases," from L. dictionarius "of words," from dictio "word." Probably first Eng. use in title of a book was in Sir Thomas Elyot's "Latin Dictionary" (1538) though L. Dictionarius was so used from c.1225.
dictum: 1670, from L. dictum "thing said," neut. of dictus, pp. of dicere "say" (see diction). In legal use, a judge's expression of opinion which is not the formal resolution of a case.
didactic: 1658, from Fr. didactique, from Gk. didaktikos "apt at teaching," from didaktos "taught," from didaskein "teach," from PIE base *dens- "wisdom, to teach, learn."
diddle: "to cheat, swindle," 1806, from dial. duddle, diddle "to totter" (1632). Meaning "waste time" is recorded from 1825. Meaning "to have sex with" is from 1879; that of "to masturbate" (especially of women) is from 1950s. More or less unrelated meanings that have gathered around a suggestive sound.
didgeridoo: 1924, Australian, of imitative origin.
dido: "prank, caper," 1807, Amer.Eng. slang, perhaps from the queen in the "Aeneid." Usually in phrase to cut didoes.
didst: archaic 2nd pers. sing. past indic. of do (q.v.).
die (v.): c.1135, possibly from O.Dan. døja or O.N. deyja "to die, pass away," both from P.Gmc. *dawjanan, from PIE base *dheu- "to pass away, become senseless." It has been speculated that O.E. had *diegan, from the same source, but it is not in any of the surviving texts and the preferred words were steorfan (see starve), sweltan (see swelter), wesan dead, also forðgan and other euphemisms. Languages usually don't borrow words from abroad for central life experiences, but "die" words are an exception, since they are often hidden or changed euphemistically out of superstitious dread. A Du. euphemism translates as "to give the pipe to Maarten." Regularly spelled dege through 15c., and still pronounced "dee" by some in Lancashire and Scotland. Used figuratively (of sounds, etc.) from 1581. Die-hard is 1844 as a noun, specifically of the 57th Regiment of Foot in the British Army; 1877 as an adj.
die (n.): c.1330 (as a plural), from O.Fr. de, of uncertain origin, perhaps from L. datum "given," pp. of dare (see date (1)), which, in addition to "give," had a secondary sense of "to play" (as a chess piece); or else from "what is given" (by chance or Fortune). Sense of "stamping block or tool" first recorded 1699.
dieresis: 1611, from L.L. diæresis, from Gk. diairesis "division," from diairein "to divide, separate," from dia- "apart" + hairein "to take."
Dies Iræ: lit. "day of wrath," first words of L. hymn of Last Judgment, attributed to Thomas of Celano (c.1250). For dies, see diurnal.
diesel: 1894, named for Rudolf Diesel (1858-1913), Ger. mechanical engineer who designed this type of engine.
diet (1): "regular food," c.1225, from O.Fr. diete, from M.L. dieta "parliamentary assembly," also "a day's work, diet, daily food allowance," from L. diaeta "prescribed way of life," from Gk. diaita, originally "way of life, regimen, dwelling," from diaitasthai "lead one's life," and from diaitan, originally "separate, select" (food and drink), freq. of *diainysthai "take apart," from dia- "apart" + ainysthai "take," from PIE base *ai- "to give, allot." Often with a sense of restriction since 14c.; hence put (someone) on a diet (c.1440). The verb meaning "to regulate oneself as to food" (especially against fatness) is from 1660. An obsolete word for this is banting (q.v.). The adj. in this sense (Diet Coke, etc.) is from 1963, originally Amer.Eng.
diet (2): "assembly," c.1450, from M.L. dieta, var. of diaeta "daily office (of the Church), daily duty, assembly, meeting of counselors," from Gk. diaita (see diet (1)), but assoc. with L. dies "day" (see diurnal).
differ: c.1375, from O.Fr. diferer, from L. differre "to set apart, differ," from dis- "away from" + ferre "carry" (see infer). Two senses that were present in L. have gone separate ways in Eng. since c.1500 with defer (transitive) and differ (intransitive).
difference: 1340, from O.Fr. difference, from L. differentia, from differentem (nom. differens), prp. of differre "to set apart" (see differ). Sense of "a quarrel" first attested 1387. Colloquial phrase what's the diff? first recorded 1896. Different is from c.1384; differential is from 1647; differentiate first attested 1816, on model of Fr. différencier; originally a mathematical term, trans. and non-technical sense of "discriminate between" is from 1876. Earlier, difference had been used as a verb in this sense.
difficulty: 1382, from O.Fr. difficulte, from L. difficultatem (nom. difficultus), from difficilis "hard," from dis- "not, away from" + facilis "easy" (see facile). Difficult is a c.1400 back-formation.
diffidence: 1526, from L. diffidentia "want of confidence," from diffidere "to mistrust, lack confidence," from dis- "away" + fidere "to trust" (see faith). Modern sense is of "distrusting oneself" (1651). The original sense was the opposite of confidence.
diffraction $Look up diffraction at Dictionary.com$: 1671, from Fr. diffraction, from Mod.L. diffractionem, from L. diffrac-, stem of diffringere "break in pieces," from dis- "apart" + frangere "to break" (see fraction).
diffusion: c.1374, from L. diffusionem, from stem of diffundere "scatter, pour out," from dif- "apart, in every direction" + fundere "pour" (see found (2)).
dig: c.1320 (diggen), of uncertain origin, probably related to dike and ditch, either via O.Fr. diguer (ult. from a Gmc. source), or directly from an unrecorded O.E. word. Native words were deolfan, grafan (medial -f- pronounced as "v" in O.E.). Meaning "thrust or poke" (as with an elbow) is from 1819; figurative sense of this is from 1840. Slang sense of "understand" first recorded 1934 in Black English, probably based on the notion of "excavate." A slightly varied sense of "appreciate" emerged 1939. Noun meaning "archaeological expedition" is from 1896. Digs "lodgings" is slang from 1893.
digamist: "person who has married a second time," 1656, from di- + gamy (see bigamy).
digest (n.): "collection of writing," 1387, from L. digestus, pp. of digerere "to separate, divide, arrange," from dis- "apart" + gerere "to carry."
digest (v.): "assimilate food in bowels," c.1460 (digestion is attested from c.1386), from L. digestus (see digest (n.)).
digit: 1398, 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 (1656) 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: c.1225, 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 1672.
digression: c.1374, 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.
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: 1393, from O.Fr. dilater, from L. dilatare "make wider, enlarge," from dis- "apart" + latus "wide" (see latitude)
dilatory: 1535, 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: 1340, 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."
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" (1377), from O.Fr. disme, from L. decima (pars) "tenth (part)," from decem "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.