Danube Look up Danube at Dictionary.com
major river of Europe (German Donau, Hungarian Duna, Russian Dunaj), from Latin Danuvius, from Celtic *danu(w)-yo-, from PIE *danu- "river" (compare Don, Dnieper, Dniester).
Daoism (n.) Look up Daoism at Dictionary.com
alternative Romanization of Taoism (q.v.).
dap (n.) Look up dap at Dictionary.com
fist-bump greeting, with various theories as to origin and name meaning. In African-American popular culture by 1972 and controversial during the Vietnam War when used by U.S. soldiers, as it often was regarded by whites as a ritual act of black solidarity. Probably imitative (dap was used in 19c. for the bounce of a ball or the skip of a stone on water). Dap, meanwhile, is listed in the DAS as African-American vernacular c. 1950 for "aware, up to date," also "stylish, well-dressed," in the latter case at least a shortening of dapper.
Daphne Look up Daphne at Dictionary.com
fem. proper name, from Greek daphne "laurel, bay tree;" in mythology the name of a nymph, daughter of the river Peneus, metamorphosed into a laurel by Gaia to save her from being ravished as she was pursued by Apollo.
dapper (adj.) Look up dapper at Dictionary.com
mid-15c., "elegant," from Middle Dutch or Middle Low German dapper "bold, strong, sturdy," later "quick, nimble," from Proto-Germanic *dapraz, perhaps with ironical shift of meaning (source also of Old High German tapfar "heavy," German tapfer "brave"), from PIE root *dheb- "dense, firm, compressed."
dapple (v.) Look up dapple at Dictionary.com
early 15c. (implied in past participle adjective dappled), perhaps from a Scandinavian source akin to Old Norse depill "spot," Norwegian dape "puddle." Perhaps a back-formation from, or merger with, Middle English adjective dapple-gray "apple-gray" (late 14c.), based on resemblance to the markings on an apple (compare Old Norse apalgrar "dapple-gray"), or, as it was used of gray horses with round blotches, perhaps via resemblance to apples themselves.
dar Look up dar at Dictionary.com
Arabic word, literally "house," used in place names, such as Dar es Salaam, Tanzania, literally "House of Peace."
dare (v.) Look up dare at Dictionary.com
from first and third person singular of Old English durran "to brave danger, dare; venture, presume," from Proto-Germanic *ders- (source also of Old Norse dearr, Old High German giturran, Gothic gadaursan), from PIE *dhers- "to dare, be courageous" (source also of Sanskrit dadharsha "to be bold;" Old Persian darš- "to dare;" Greek thrasys "bold;" Old Church Slavonic druzate "to be bold, dare;" Lithuanian dristi "to dare," drasus "courageous").

An Old English irregular preterite-present verb: darr, dearst, dear were first, second and third person singular present indicative; mostly regularized 16c., though past tense dorste survived as durst, but is now dying, persisting mainly in northern English dialect. Meaning "to challenge or defy (someone)" is first recorded 1570s.
dare (n.) Look up dare at Dictionary.com
1590s, from dare (v.).
daredevil (n.) Look up daredevil at Dictionary.com
1794, "recklessly daring person," from dare (v.) + devil (n.). The devil might refer to the person, or the sense might be "one who dares the devil." Compare scarecrow, killjoy, pickpocket (n.), cutthroat, also fear-babe a 16c. word for "something that frightens children;" kill-devil "bad rum." As an adjective, from 1832.
Darfur Look up Darfur at Dictionary.com
region in Sudan, named for its people, from Arabic dar, literally "house" + Fur, ethnic name of the indigenous African population.
daring (n.) Look up daring at Dictionary.com
late 14c., verbal noun from dare (v.).
Darius Look up Darius at Dictionary.com
name of three Persian rulers, notably Darius the Great, Persian emperor 521-485 B.C.E., from Greek Darius, from Old Persian Darayavaus, probably literally "he who holds firm the good," from PIE root *dher- (2) "to hold firmly, support" (see firm (adj.)).
Darjeeling Look up Darjeeling at Dictionary.com
town in northeastern India, from Tibetan dojeling "diamond island," in reference to Vajrayana (literally "vehicle of the diamond") Buddhism. The "island" being the high ground of the place's site. As a type of tea, from 1882.
dark (adj.) Look up dark at Dictionary.com
Old English deorc "dark, obscure, gloomy; sad, cheerless; sinister, wicked," from Proto-Germanic *derkaz (source also of Old High German tarchanjan "to hide, conceal"). "Absence of light" especially at night is the original meaning. Application to colors is 16c. Theater slang for "closed" is from 1916.
dark (n.) Look up dark at Dictionary.com
early 13c., from dark (adj.). Figurative in the dark "ignorant" first recorded 1670s.
dark ages Look up dark ages at Dictionary.com
1739, any benighted time in history, period of ignorance; specific focus on the centuries from the fall of Rome to the revival of secular literature is from 1830s.
dark horse (n.) Look up dark horse at Dictionary.com
in politics, 1842, an image from horse racing, in which dark is used in its figurative sense of "unknown."
Moonraker is called a "dark horse"; that is neither his sire nor dam is known. ["Pierce Egan's Book of Sports," London, 1832]
darken (v.) Look up darken at Dictionary.com
c. 1300, "to make dark;" late 14c., "to become dark," from dark (adj.) + -en (1). The more usual verb in Middle English was simply dark, as it is in Chaucer and Shakespeare, and darken did not predominate until 17c. The Anglo-Saxons also had a verb sweorcan meaning "to grow dark." To darken someone's door (usually with a negative) is attested from 1729.
darkling (adv.) Look up darkling at Dictionary.com
"in the dark," mid-15c., from dark (n.) + now-obsolete adverbial ending -ling (compare headlong).
But having nothing to do with the participial -ing it does not mean growing dark &c.; from the mistaken notion that it is a participle spring both the misuse of the word itself and the spurious verb darkle. [Fowler]
darkly (adv.) Look up darkly at Dictionary.com
Old English deorclice "darkly, horribly, foully;" see dark + -ly (2).
darkness (n.) Look up darkness at Dictionary.com
Old English deorcnysse, from dark + -ness. Figurative use is recorded from mid-14c. The 10c. Anglo-Saxon treatise on astronomy uses þeostrum for "darkness."
darky (n.) Look up darky at Dictionary.com
"black person" (now offensive), 1775, from dark (adj.) + -y (3). Related: Darkies.
darling (n.) Look up darling at Dictionary.com
Old English deorling "darling, favorite minion," double diminutive of deor "dear" (see dear (adj.)). The vowel shift from -e- to -a- (16c.) is usual for -er- followed by a consonant. "It is better to be An olde mans derlyng, than a yong mans werlyng" (1562).
darn (v.) Look up darn at Dictionary.com
"to mend" c. 1600, perhaps from Middle French darner "mend," from darne "piece," from Breton darn "piece, fragment, part." Alternative etymology is from obsolete dern (see dern). Related: Darned; darning.
darn (interj.) Look up darn at Dictionary.com
tame curse word, 1781, American English euphemism for damn, said to have originated in New England when swearing was a punishable offense; if so, its spread was probably influenced by 'tarnal, short for Eternal, as in By the Eternal (God), favorite exclamation of Andrew Jackson, among others (see tarnation). Related: darned (past participle adjective, 1806); darndest (superlative, 1844).
darnel (n.) Look up darnel at Dictionary.com
weed growing in grainfields, c. 1300, from northern dialectal French darnelle; according to one theory the the second element is Old French neelle (Modern French nielle) "cockle," from Vulgar Latin nigella "black-seeded," from fem. of Latin nigellus "blackish."

But perhaps rather the word is related to Middle Dutch verdaernt, verdarnt "stunned, dumbfounded, angry," Walloon darne, derne "stunned, dazed, drunk," the plant being so called from its well-known inebriating quality (actually caused by fungus growing on the plant); the French word for it is ivraie, from Latin ebriacus "intoxicated," and the botanical name, Lolium temulentum, is from Latin temulent "drunken," though this sometimes is said to be "from the heavy seed heads lolling over under their own weight."
In some parts of continental Europe it appears the seeds of darnel have the reputation of causing intoxication in men, beasts, and birds, the effects being sometimes so violent as to produce convulsions. In Scotland the name of Sleepies, is applied to darnel, from the seeds causing narcotic effects. [Gouverneur Emerson, "The American Farmer's Encyclopedia," New York, 1860. It also mentions that "Haller speaks of them as communicating these properties to beer."]
dart (n.) Look up dart at Dictionary.com
early 14c., from Old French dart "throwing spear, arrow," from Proto-Germanic *darothuz source also of Old English daroð, Old High German tart, Old Norse darraþr "dart"). Italian and Spanish dardo are said to be from Germanic by way of Old Provençal.
dart (v.) Look up dart at Dictionary.com
late 14c., "to pierce with a dart," from dart (n.). Meaning "to move like a dart" is attested from 1610s. Related: Darted; darter; darting.
Darwin Look up Darwin at Dictionary.com
surname attested from 12c., from Old English deorwine, literally "dear friend," probably used as a given name and also the source of the masc. proper name Derwin.
Darwinism (n.) Look up Darwinism at Dictionary.com
1864, from Charles Darwin (1809-1882), whose major works were "The Origin of Species" (1859) and "The Descent of Man" (1871), + -ism.
dash (v.) Look up dash at Dictionary.com
c. 1300, probably from a Scandinavian source (compare Swedish daska, Danish daske "to beat, strike"), somehow imitative. The oldest sense is that in dash to pieces and dashed hopes. Intransitive meaning "move quickly" appeared c. 1300, that of "to write hurriedly" is 1726. Related: Dashed; dashing.
dash (n.) Look up dash at Dictionary.com
late 14c., from dash (v.). Sporting sense is from 1881, originally "race run in one heat."
dashboard (n.) Look up dashboard at Dictionary.com
1846, from dash (v.) + board (n.1); "board in front of a carriage to stop mud from being splashed ("dashed") into the vehicle by the horse's hoofs." Of motor vehicles, from 1904.
dashiki (n.) Look up dashiki at Dictionary.com
1969, of West African origin.
dashing (adj.) Look up dashing at Dictionary.com
1801, "given to cutting a dash" (1786), which was a colloquial expression for "acting brilliantly," from dash (n.) in the sense of "showy appearance," which is attested from 1715. The sense of "splashing" is recorded from mid-15c.
dastard (n.) Look up dastard at Dictionary.com
mid-15c., "one who is lazy or dull;" an English formation on a French model, probably from *dast, "dazed," past participle of dasen "to daze" (see daze (v.)) + deprecatory suffix -ard. Meaning "one who shirks from danger" is late 15c.
dastardly (adj.) Look up dastardly at Dictionary.com
1560s, "showing despicable cowardice," originally "dull," from Middle English dastard + -ly (1).
dat Look up dat at Dictionary.com
representing the pronunciation of that in West Indian, Irish, or African-American vernacular speech, from 1680s.
data (n.) Look up data at Dictionary.com
1640s, plural of datum, from Latin datum "(thing) given," neuter past participle of dare "to give" (see date (n.1)). Meaning "transmittable and storable computer information" first recorded 1946. Data processing is from 1954.
data base (n.) Look up data base at Dictionary.com
also database, attested from 1962, from data + base (n.).
date (n.1) Look up date at Dictionary.com
"time," early 14c., from Old French date (13c.) "date, day; time," from Medieval Latin data, noun use of fem. singular of Latin datus "given," past participle of dare "to give, grant, offer," from PIE root *do- "to give" (source also of Sanskrit dadati "gives," danam "offering, present;" Old Persian dadatuv "let him give," Old Church Slavonic dati "give," dani "tribute;" Latin donum "gift;" Greek didomi, didonai, "to give, offer," doron "gift;" Lithuanian duonis "gift," Old Irish dan "gift, endowment, talent," Welsh dawn "gift").

The Roman convention of closing every article of correspondence by writing "given" and the day and month -- meaning perhaps "given to messenger" -- led to data becoming a term for "the time (and place) stated." (a Roman letter would include something along the lines of datum Romae pridie Kalendas Maias -- "given at Rome on the last day of April."
date (n.2) Look up date at Dictionary.com
the fruit, late 13c., from Old French date, from Old Provençal datil, from Latin dactylus, from Greek daktylos "date," originally "finger, toe;" so called because of fancied resemblance between oblong fruit of the date palm and human digits. Possibly from a Semitic source (compare Hebrew deqel, Aramaic diqla, Arabic daqal "date palm") and assimilated to the Greek word for "finger."
date (n.3) Look up date at Dictionary.com
"liaison," 1885, gradually evolving from date (n.1) in its general sense of "appointment;" romantic sense by 1890s. Meaning "person one has a date with" is from 1925.
date (v.2) Look up date at Dictionary.com
"have a romantic liaison;" 1902, from date (n.3). Related: Dated; dating.
date (v.1) Look up date at Dictionary.com
"to mark (a document) with the date," late 14c., from date (n.1). Meaning "to assign to or indicate a date" (of an event) is from c. 1400. Meaning "to mark as old-fashioned" is from 1895. Related: Dated; dating.
date rape (n.) Look up date rape at Dictionary.com
by 1973, from date (n.3) + rape (n.1).
dated (adj.) Look up dated at Dictionary.com
"old-fashioned," 1900, past participle adjective from date (v.1).
dateline (n.) Look up dateline at Dictionary.com
1880, imaginary line down the Pacific Ocean on which the calendar day begins and ends, from date (n.1) + line (n.). Meaning "line of text that tells the date and place of origin of a newspaper, article, telegram, etc." is from 1888.
dative (adj.) Look up dative at Dictionary.com
mid-15c., from Latin dativus "pertaining to giving," from datus "given" (see date (n.1)); in grammatical use from Greek dotike (ptosis) "dative (case)," from dotikos "of giving nature," from dotos "given," from PIE root *do- "to give," from the same PIE root as the Latin word. In law, "that may be disposed of at pleasure," from 1530s. Typically the case of the indirect object, but sometimes also denoting "motion toward." In old Germanic languages, the "fourth case," catch-all for Indo-European dative, ablative, locative, and other cases.