Online Etymology Dictionary

delf: late O.E. dælf "trench, ditch, quarry," from gedelf "digging, a digging," from delfan "to dig" (see delve).
Delft: town in Holland,named from its chief canal, from Du. delf, lit. "ditch, canal;" which is related to O.E. dælf and modern delve. As a short form of delftware, attested from 1714.
delftware: 1714, from Delft, town in Holland where the glazed earthenware was made, + ware.
Delhi: city in India, of unknown origin, perhaps connected to Hindi dehli "threshhold," with reference to the watershed boundary between the Ganges and Indus, which is nearby.
deli: 1954, short for delicatessen.
Delian: 1620s, "of Delos, tiny Gk. island in the Aegean, birthplace of Apollo and Artemis. Delian problem "find the length of the side of a cube having double the volume of a given cube," was set by the oracle at Delos when it answered (430 B.C.E.) that the plague in Athens would end when Apollo's (cube-shaped) altar was doubled.
deliberate (adj.): 1540s, "done with careful consideration," from L. deliberatus, pp. of deliberare (see deliberation). Meaning "slow, consciously unhurried" is attested by 1590s.
deliberate (v.): 1540s, from L. deliberat-, pp. stem of deliberare (see deliberation). Related: Deliberated (1590s); deliberately (1530s); deliberating (1640s).
deliberation: late 14c., from L. deliberationem, from deliberare "weigh, consider well," from de- "entirely" + -liberare, altered (perhaps by influence of liberare "liberate") from librare "to balance, weigh," from libra "scale."
deliberative: 1550s, from L. deliberativus, from pp. stem of deliberare (see deliberation).
delibrate: 1620s, "to pull off the bark of a tree," from L. delibrare, from de- + liber "bark" (see library).
delicacies: "things dainty and gratifying to the palate," mid-15c., from plural of delicacy.
delicacy: late 14c., "quaity of being addicted to sensuous pleasure," from delicate. Meaning "fineness, softness, tender loveliness" is from 1580s; that of "weakness of constitution" is from 1630s. Meaning "a dainty viand" is from mid-15c.
delicate: late 14c., from L. delicatus "alluring, delightful, dainty," also "addicted to pleasure," of unknown origin; related by folk etymology (and perhaps genuinely) to deliciæ "a pet," and delicere "to allure, entice." Meaning "feeble in constitution" is c.1400; that of "easily broken" is recorded from 1560s.
delicatessen: 1889, Amer.Eng. borrowing from Ger. delikatessen, plural of delikatesse "a delicacy, fine food," from Fr. delicatesse (1560s), from delicat "fine," from L. delicatus (see delicate).
delicious: c.1300, from O.Fr. delicieus, from L.L. deliciosus "delicious, delicate," from L. delicia (pl. deliciæ) "a delight," from delicere "to allure, entice," from de- "away" + lacere "lure, deceive." As a name of a type of apple, attested from 1903, first grown by Jesse Hiatt of Iowa, U.S.A. Colloquial shortening delish is attested from 1920.
delict: 1520s, from L. delictum "fault, offense, crime," neut. sing. of pp. of delinquere (see delinquent). Phrase in flagrant delict translates L. in flagrante delicto.
deligate: 1840, from L. deligatus "bound fast," from deligare "to bind fast," from de- + ligare "to bind" (see ligament).
deligation: 1660s, from L. *deligationem, noun of action from deligare (see deligate).
delight: early 13c., delit, from O.Fr. delit, from delitier "please greatly, charm," from L. delectare "to allure, delight," freq. of delicere "entice" (see delicious). Spelled delite until 16c. when it changed under influence of light, flight, etc. Related: Delightful (1520s).
Delilah: "temptress, treacherous lover," 1590s, from the name of the woman who seduced and betrayed Samson in Judges.
delimit: 1852, from Fr. delimiter (18c.), from L. delimitare "to mark out as a boundary," from de- + limitare, from limitem, limes "boundary, limit."
delimitation: 1836, from Fr. délimitation (18c.), noun of action from délimiter (see delimit). Related: Delimited.
delimiter: 1960, in computing, from delimit.
delineate: 1550s, from L. delineatus, pp. of delineare, from de- "completely" + lineare "draw lines," from linea "line" (see line (n.)).
delineation: 1560s, from L. delineationem, noun of action from delineare (see delineate).
delinquency: 1630s, from L. delinquentia, from delinquentem (see delinquent).
delinquent: late 15c., from L. delinquentum (nom. delinquens), prp. of delinquere, from de- "completely" + linquere "to leave" (see relinquish). The adj. and noun are equally old in English.
deliquesce: 1756, in chemistry, from L. deliquescere "to melt away," from de- + liquescere "to melt," from liquere "to be liquid" (see liquid). General use dates from 1858.
deliquescent: 1791, in chemistry, from L. deliquescentem, prp. of deliquescere (see deliquesce). General use dates from 1866.
delirious: 1703, from L. delirium (see delirium). Figurative use attested from 1791. Related: Deliriously (1820).
delirium: 1590s, from L. delirium "madness," from deliriare "be crazy, rave," lit. "go off the furrow," a plowing metaphor, from phrase de lire (de "off, away" + lira "furrow").
delirium tremens: 1813, medical L., lit. "trembling delirium," introduced 1813 by British physician Thomas Sutton, for "that form of delirium which is rendered worse by bleeding, but improved by opium. By Rayer and subsequent writers it has been almost exclusively applied to delirium resulting from the abuse of alcohol" [Sydenham Society Lexicon of Medicine].
deliver: early 13c., from O.Fr. delivrer, from L.L. deliberare, from L. de- "away" + liberare "to free" (see deliberation). Sense of "hand over" is late 13c., which brings it in opposition to its root. Meaning "bring to childbirth" (unburden) is c.1300; that of "project, throw" is 1590s. Related: Deliverable (1755).
deliverance: late 13c., "action of setting free" in physical or spiritual senses, from O.Fr. delivrance (12c.), from délivrer (see deliver). Formerly also with senses now restricted to delivery.
delivery: late 15c., "action of handing over to another," from Anglo-Fr. delivrée, fem. pp. of délivrer (see deliver). Childbirth sense is attested from 1570s. Of speech, from 1580s. Of a blow, throw of a ball, etc., from 1702.
dell: O.E. dell (perhaps lost and then borrowed in M.E. from cognate M.Du./M.L.G. delle), from P.Gmc. *daljo, related to dale. Uncertain relationship to dell, rogue's cant 16c.-17c. for "a young girl of the vagrant class." "A Dell is a yonge wenche, able for generation, and not yet knowen or broken by the vpright man. ... [W]hen they have beene lyen with all by the vpright man then they be Doxes, and no Dells" [Thomas Harman, "A Caveat or Warning for Common Cursitors," 1567].
Della Crusca: 1796, from It. Accademia della Crusca, lit. "Academy of the Chaff," "the name of an Academy established at Florence in 1582, mainly with the object of sifting and purifying the Italian language; whence its name, and its emblem, a sieve" [OED].
Della Robbia: 1787, from name of a family of 15c. Florentine painters and sculptors; used of wares made by Luca Della Robbia (1400-1482), or those like them.
delouse: 1919, from de- + louse; first used in reference to World War I armies.
Delphi: oracle town on slopes of Mount Parnassus, from Gk. delphis "dolphin" (see dolphin). Supposedly Apollo assumed this form to found the shrine. Related: Delphic (1590s).
delt: short for deltoid (q.v.).
delta: c.1200, Gk. letter shaped like a triangle, equivalent to our "D," the name from Phoenician daleth "tent door." Herodotus used it of the mouth of the Nile, and it was so used in Eng. from 1555; applied to other river mouths from 1790. Deltoid muscle so called since 1741, from its shape.
deltoid: 1741, in deltoid muscle, from Gk. deltoeides "triangular," lit. "shaped like the letter delta;" see delta + -oid.
delude: c.1400, from L. deludere "to mock, deceive," from de- "down, to one's detriment" + ludere "to play" (see ludicrous).
deluge (n.): late 14c., from O.Fr. deluge (12c.), earlier deluve, from L. diluvium, from diluere "wash away," from dis- "away" + -luere, comb. form of lavere "to wash" (see lave). The verb is from 1649.
delusion: "act of misleading someone," early 15c.; as a form of mental derangement, 1550s. See delude. Technically, delusion is a belief that, though false, has been surrendered to and accepted by the whole mind as a truth; illusion is an impression that, though false, is entertained provisionally on the recommendation of the senses or the imagination, but awaits full acceptance and may not influence action. Delusions of grandeur, the exact phrase, is recorded from 1840, though the two words were in close association for some time before that.
delusional: 1871, from delusion + -al (1).
delusive: c.1600, from pp. stem of L. deludere (see delude) + -ive.
deluxe: 1819, from Fr. de luxe, lit. "of luxury," from L. luxus "excess, abundance."