Online Etymology Dictionary

dinger (n.): "something superlative," 1809, American English, agent noun from ding (v.).
dinghy (n.): 1810, from Hindi dingi "small boat," perhaps from Sanskrit drona-m "wooden trough," related to dru-s "wood, tree" (see tree (n.)). The spelling with -h- is to indicate a hard -g-.
dingle (n.): "deep dell or hollow, usually wooded," mid-13c., of unknown origin; a dialectal word until it entered literary use 17c.
dingleberry (n.): by 1973, perhaps with suggestions of dangle and berry. Attested from late 19c. through 1930s as a humorous-sounding surname in comedic writing.
dingo (n.): 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 (n.): "any unspecified or unspecifiable object; something one does not know the name of or does not wish to name," 1876, U.S. slang, from Dutch dinges, literally "thing" (see thing).
dingy (adj.): 1736, Kentish dialect, "dirty," of uncertain origin, but perhaps related to dung. The noun dinge (1816) is a back-formation.
dining (n.): c. 1400, verbal noun from dine (v.). Dining room is attested from c. 1600.
DINK: acronym for double income, no kids, popular from 1987.
dink (n.): derogatory for "Vietnamese," 1969, U.S. military slang, of uncertain origin.
dinkum (n.): 1888, "hard work," Australian slang, of unknown origin, perhaps connected to Lincolnshire dialect. Meaning "honest, genuine" is attested from 1894.
dinky (adj.): 1788 "neat, trim, dainty, small," from Scottish dialectal dink "finely dressed, trim" (c. 1500), which is of unknown origin. Modern sense is 1850s.
dinner (n.): c. 1300, from Old French disner (11c.), originally "breakfast," later "lunch," noun use of infinitive disner (see dine). Always used in English 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 (n.): 1841, coined in Modern Latin by Sir Richard Owen, from comb. form of Greek deinos "terrible" (see dire) + sauros "lizard" (see -saurus). Figurative sense of "person or institution not adapting to change" is from 1952.
dint (n.): Old English dynt "blow dealt in fighting" (especially by a sword), from Proto-Germanic *duntiz (source also of Old Norse dyntr "blow, kick"). Phrase by dint of ... "by force of, by means of," is early 14c.
diocesan (adj.): mid-15c., from French diocésain (15c.), from diocese (see diocese).
diocese (n.): early 14c., from Old French diocese (13c., Modern French diocèse), from Late Latin diocesis "a governor's jurisdiction," later, "a bishop's jurisdiction," from Greek dioikesis "government, administration; province," originally "economy, housekeeping," from dioikein "control, govern, administer, manage a house," from dia- "thoroughly" (see dia-) + oikos "house" (see villa).
diode (n.): 1886, from Greek di- "twice" + hodos "way" (see cede).
Diomedes: Greek hero in the Trojan War, literally "advised by Zeus," from Dios, genitive of Zeus (see Zeus) + medos "counsel, plan, device, cunning" (see Medea).
Dion: masc. proper name, short for Dionysius (see Dennis).
Dionysian (adj.): of or pertaining to Dionysos (Latin Dionysus), Greek god of wine and revelry, identified with Roman Bacchus. His name is of unknown origin. Or in reference to historical men named Dionysius such as the tyrants of Syracuse and especially Dionysius Exiguus (see A.D.), such as Dionysian period of 532 Julian years, when the moon phases recur on the same days of the week.
diorama (n.): 1823 as a type of picture-viewing device, from French diorama (1822), from Greek di- "through" (see dia-) + orama "that which is seen, a sight" (see panorama). Meaning "small-scale replica of a scene, etc." is from 1902.
Dioscuri (n.): Latinized form of Greek Dioskouroi, literally "Zeus' boys," from Dios, genitive of Zeus (see Zeus) + kouroi, plural of kouros "boy, son" (see crescent).
dioxin (n.): 1919, from dioxy- + chemical suffix -in (2). All the compounds in the group are characterized by two oxygen atoms.
dip (v.): Old English dyppan "immerse, baptize by immersion," from Proto-Germanic *duppjan (source also of Old Norse deypa "to dip," Danish døbe "to baptize," Old Frisian depa, Dutch dopen, German taufen, Gothic daupjan "to baptize"), related to Old English diepan "immerse, dip," and perhaps ultimately to deep. As a noun, from 1590s. Sense of "downward slope" is 1708. Meaning "sweet sauce for pudding, etc." first recorded 1825.
dip (n.): "stupid person, eccentric person," 1920s slang, perhaps a back-formation from dippy. "Dipshit is an emphatic form of dip (2); dipstick may be a euphemism or may reflect putative dipstick 'penis' " [DAS].
diphtheria (n.): from French diphthérie, coined 1857 by physician Pierre Bretonneau (1778-1862) from Greek diphthera "prepared hide, leather," which is of unknown origin; the disease so called for the tough membrane that forms in the throat. Bretonneau's earlier name for it was diphthérite, Englished as diphtheritis (1826). Formerly known in England as the Boulogne sore throat, because it spread from France.
diphthong (n.): late 15c., from Middle French diphthongue, from Late Latin diphthongus, from Greek diphthongos "having two sounds," from di- "double" (see di- (1)) + phthongos "sound, voice," related to phthengesthai "utter, speak loudly."
diplodocus (n.): 1884, coined in Modern Latin in 1878 by U.S. paleontologist Othniel Charles Marsh (1831-1899) from Greek diploos "double" (see diploid) + dokos "a beam." So called for the peculiar structure of the tail bones.
diploid (adj.): 1908, from Greek diploos "double, twofold," (from di- "two" + root *pel- "to fold;" see ply (v.)) + eidos "form" (see -oid).
diploma (n.): 1640s, "state paper, official document," from Latin diploma, from Greek diploma "licence, chart," originally "paper folded double," from diploun "to double, fold over," from diploos "double" (see diploid) + -oma. Specific academic sense is 1680s in English.
diplomacy (n.): 1796, from French diplomatie, formed from diplomate "diplomat" (on model of aristocratie from aristocrate), from Latin adjective diplomaticos, from diploma (genitive diplomatis) "official document conferring a privilege" (see diploma; for sense evolution, see diplomatic).
It is obvious to any one who has been in charge of the interests of his country abroad that the day secrecy is abolished negotiations of any kind will become impossible. [Jules Cambon, "The Diplomatist" (transl. Christopher Rede Turner), 1931]
diplomat (n.): 1813, from French diplomate, a back-formation from diplomatique (see diplomatic) on model of aristocrate from aristocratique.
diplomatic (adj.): 1711, "pertaining to documents, texts, charters," from Medieval Latin diplomaticus, from diplomat-, stem of diploma (see diploma).

Meaning "pertaining to international relations" is recorded from 1787, apparently a sense evolved in 18c. from the use of diplomaticus in Modern Latin titles of collections of international treaties, etc., in which the word referred to the "texts" but came to be felt as meaning "pertaining to international relations." In the general sense of "tactful and adroit," it dates from 1826. Related: Diplomatically.
dipper (n.): late 14c., as a type of diving bird, agent noun from dip (v.). As a ladle or long-handled utensil for drawing liquid, from 1783, chiefly American English. As the popular U.S. name for the asterism known in Britain as The Plough or Charles' Wain, attested by 1833.
dippy (adj.): "mad, insane, crazy," 1903, perhaps from dip + -y (2), but the exact signification is unclear. Another theory connects it with dipsomania.
dipsomania (n.): 1843, "morbid craving for alcohol," coined in medical Latin from Greek dipsa "thirst" (which is of unknown origin) + mania.
dipsomaniac (n.): "drunkard," 1858, from dipsomania; slang shortening dipso is from 1880.
diptych (n.): 1620s, from Latin diptycha (plural), from late Greek diptykha, neuter plural of diptykhos "double-folded, doubled," from dis- "two" + ptykhe "fold."
dire (adj.): 1560s, from Latin dirus "fearful, awful, boding ill," which is of unknown origin; perhaps from Oscan and Umbrian and perhaps cognate with Greek deinos, from PIE root *dwei-.
direct (v.): late 14c., "to write (to someone), to address," from Latin directus "straight," past participle of dirigere "set straight," from dis- "apart" (see dis-) + regere "to direct, to guide, keep straight" (see regal). Compare dress; address.

Meaning "to govern, regulate" is from c. 1500; "to order, ordain" is from 1650s. Sense of "to write the destination on the outside of a letter" is from 16c. Of plays, films, etc., from 1913. Related: Directed; directing.
direct (adj.): late 14c., from Latin directus "straight," past participle of dirigere "set straight" (see direct (v.)).
direction (n.): c. 1400, "orderly arrangement;" c. 1500 as "action of directing," from Latin directionem (nominative directio), noun of action from past participle stem of dirigere (see direct (v.)). Meaning "course pursued by a moving object" is from 1660s. Related: Directional.
directions (n.): "instructions on how to get somewhere," 1590s, plural of direction (q.v.).
directive (adj.): mid-15c., from Medieval Latin directivus, from past participle stem of Latin dirigere (see direct (v.)). From 1640s as a noun.
directly (adv.): 1510s, "in a straight line," from direct (adj.) + -ly (2). Figurative use is slightly earlier (c. 1500). Meaning "at once, immediately in time" (c. 1600) is from earlier sense of "without intermediate steps" (1520s).
director (n.): late 15c., "a guide," from Anglo-French directour, French directeur, agent noun from Latin dirigere (see direct (v.)). Corporate sense is from 1630s; theatrical sense from 1911.
directorate (n.): 1837, from director + -ate (1).
directory (n.): 1540s, "guide, book of rules," from Medieval Latin directorium, noun use of neuter of Latin directorius, from directus (see direct (v.)). Meaning "alphabetical listing of inhabitants of a region" is from 1732; listing of telephone numbers is from 1908. As an adjective, from mid-15c.
dirge (n.): early 13c., dirige (current contracted form is from c. 1400), from Latin dirige "direct!" imperative of dirigere "to direct," probably from antiphon Dirige, Domine, Deus meus, in conspectu tuo viam meam, "Direct, O Lord, my God, my way in thy sight," from Psalm v:9, which opened the Matins service in the Office of the Dead. Transferred sense of "any funeral song" is from c. 1500.