Online Etymology Dictionary

demystify (v.): 1963; see de- + mystify. Related: Demystified; demystifying.
den (n.): Old English denn "wild animal's lair," from Proto-Germanic *danjan (source also of Middle Low German denne "lowland, wooded vale, den," Old English denu "valley," Old Frisian dene "down," Old High German tenni, German tenne "threshing floor," from PIE *dan- "low ground"). Sense of "small room" is 1771, originally colloquial.
denarius (n.): ancient Roman silver coin, 1570s, from Latin denarius, noun use of adjective meaning "containing ten," and short for denarius nummus "the coin containing ten (aces)," from deni- "by tens," from decem "ten" (see ten).
denationalize (v.): 1807, "to deprive of nationality," from French dénationaliser (said in contemporary English publications to have been coined by Napoleon Buonaparte; denapoleonize was coined shortly thereafter); see de- + nationalize. Meaning "to transfer from national to private ownership" recorded from 1921. Related: Denationalized; denationalization.
denaturation (n.): 1845, earlier in French and German; see denature + -ation.
denature (v.): 1878, in modern sense, from French dénaturer (Old French desnaturer "change the nature of; make unnatural"); see de- + nature. Earlier "to make unnatural" (1680s). Related: Denatured.
dendrite (n.): mid-18c., from Greek dendrites "of or pertaining to a tree," from dendron "tree" (see dendro-). The mineral so called for its markings.
dendritic (adj.): 1816; see dendrite + -ic.
dendro-: word-forming element meaning "tree," from Greek dendro-, comb. form of dendron "tree," sometimes especially "fruit tree" (as opposed to hyle "timber"), from PIE *der-drew-, from root *deru- "to be firm, solid, steadfast," specifically used for "wood, tree" (see tree (n.)).
dendrochronology (n.): "dating by tree rings," 1928; see dendro- + chronology.
dendrology (n.): 1708, from dendro- + -ology.
dene (n.2): "bare, sandy tract by the sea," late 13c., of uncertain origin, perhaps connected to dune, but the sense difference is difficult.
dene (n.1): "small valley," from Old English denu "valley" (see den).
Deneb: bright star in the tail of the constellation Cygnus the Swan, 1741, from Arabic Al Dhanab al Dajajah "the Hen's Tail."
Denebola: second-brightest star in Leo, from Latinized corruption of Arabic dhanab al-(asad) "tail of the lion." In 18c., often simply Deneb.
dengue (n.): 1828, from West Indian Spanish dengue, from an African source, perhaps Swahili dinga "seizure, cramp," form influenced by Spanish dengue "prudery" (perhaps because sufferers walk stiffly and erect due to painful joints). The disease is African, introduced to the West Indies 1827.
denial (n.): 1520s; see deny + -al (2). Replaced earlier denyance (mid-15c.). Meaning "unconscious suppression of painful or embarrassing feelings" first attested 1914 in A.A. Brill's translation of Freud's "Psychopathology of Everyday Life"; phrase in denial popularized 1980s.
denier (n.): French coin, early 15c., from Old French dener, a small coin of slight value, roughly equivalent to the English penny, in use in France from the time of Charlemagne to early modern times, from Latin denarium, from denarius, name of a Roman coin (source also of Spanish dinero; see denarius).
denigrate (v.): 1520s, from Latin denigratus, past participle of denigrare "to blacken, defame," from de- "completely" (see de-) + nigr-, stem of niger "black" (see Negro). which is of unknown origin. "Apparently disused in 18th c. and revived in 19th c." [OED]. Related: Denigrated; denigrating.
denigration (n.): early 15c., from Late Latin denigrationem (nominative denigratio), noun of action from past participle stem of Latin denigrare (see denigrate).
denim (n.): 1690s, from French serge de Nîmes "serge from Nîmes," town in southern France. Application to "coarse cotton cloth" is first recorded 1850 in American English. Denims "pants made of denim" recorded from 1868. The place name is Roman Nemausus, said to be ultimately from Gaulish nemo "sanctuary."
Denise: fem. form of masc. proper name Dennis. Little used in U.S. before 1920s; was at its most popular (top 50) for girls born between 1951 and 1973.
denitrification (n.): 1883; see de- + nitrification. Related: Denitrate; denitrify.
denizen (n.): early 15c., from Anglo-French deinzein, from deinz "within, inside," from Late Latin deintus, from de- "from" + intus "within" (see ento-). Historically, an alien admitted to certain rights of citizenship; a naturalized citizen.
Denmark: from Dane, the people's name, + Danish mark "border" (see mark (n.1)).
Dennis: masc. proper name, from French Denis, ultimately from Latin Dionysius, name of an important 6c. Church father, from Greek Dionysos, god of wine and revelry.
denominate (v.): 1550s, from Latin denominatus, past participle of denominare "to name" (see denomination). Related: Denominated; denominating.
denomination (n.): late 14c., "a naming, act of giving a name to," from Old French denominacion "nominating, naming," from Latin denominationem (nominative denominatio) "a calling by anything other than the proper name, metonymy," from denominare "to name," from de- "completely" (see de-) + nominare "to name" (see nominate). Meaning "a class" is from mid-15c. Monetary sense is 1650s; meaning "religious sect" is 1716.
denominational (adj.): 1838; see denomination + -al (1).
denominative (adj.): early 15c., "in name only," from Late Latin denominativus, from Latin denominatus (see denominate).
denominator (n.): 1540s, in mathematics, from Medieval Latin denominator, agent noun from past participle stem of denominare (see denomination).
denotate (v.): 1590s, from past participle stem of Latin denotare (see denote). Related: Denotated; denotating.
denotation (n.): 1530s, "indication," from Late Latin denotationem (nominative denotatio), noun of action from past participle stem of denotare (see denote). As a term in logic, from 1843 (contrasted with connotation).
denotative (adj.): 1610s, from Latin denotat-, past participle stem of denotare (see denote) + -ive.
denote (v.): 1590s, from Middle French dénoter (14c.), from Latin denotare "denote, mark out," from de- "completely" (see de-) + notare "to mark" (see note (v.)). Related: Denoted; denoting.
denouement (n.): 1752, from French dénouement "an untying" (of plot), from dénouer "untie" (Old French desnouer) from des- "un-, out" (see dis-) + nouer "to tie, knot," from Latin nodus "a knot," from PIE *ned- "to bind, tie" (see net (n.)).
denounce (v.): early 14c., "announce," from Old French denoncier (12c., Modern French dénoncer), from Latin denuntiare "to announce, proclaim; denounce, menace; command, order," from de- "down" + nuntiare "proclaim, announce," from nuntius "messenger" (see nuncio). Negative sense in English via meaning "to declare or proclaim" something as cursed, excommunicated, forgiven, removed from office. Related: Denounced; denouncing.
dense (adj.): early 15c., from Middle French dense and directly from Latin densus "thick, crowded; cloudy," perhaps from PIE root *dens- "dense, thick" (source also of Greek dasus "hairy, shaggy"). Sense of "stupid" is first recorded 1822.
density (n.): c. 1600, from French densité (16c.), from Old French dempsité (13c.), from Latin densitas "thickness," from densus "thick, dense" (see dense).
dent (n.): early 14c., "a strike or blow," dialectal variant of Middle English dint (q.v.); sense of "indentation" first recorded 1560s, apparently influenced by indent.
dent (v.): late 14c., from dent (n.). Related: Dented; denting.
dental (adj.): 1590s, from Middle French dental "of teeth" or Medieval Latin dentalis, from Latin dens (genitive dentis) "tooth," from PIE root *dent- (see tooth).
dentifrice (n.): early 15c., from Middle French dentifrice (15c.), from Latin dentifricium "powder for rubbing the teeth," from dens (genitive dentis) "tooth" (see tooth) + fricare "to rub" (see friction).
dentin (n.): also dentine, the hard substance in teeth, 1836, from comb. form of Latin dens (genitive dentis) "tooth" (see tooth) + chemical suffix -in (2).
dentist (n.): 1759, from French dentiste, from dent "tooth," from Latin dens (see tooth) + -ist.
Dentist figures it now in our newspapers, and may do well enough for a French puffer, but we fancy Rutter is content with being called a tooth-drawer ["Edinburgh Chronicle," Sept. 15, 1759].
Tooth-drawer is attested from late 14c.
dentistry (n.): 1838; see dentist + -ry.
dentition (n.): 1610s, "teething, the cutting of teeth," from Latin dentitionem (nominative dentitio) "teething," noun of action from past participle stem of dentire "to cut the teeth," from dentem (nominative dens) "tooth" (see tooth). Meaning "arrangement of teeth" is from 1849.
denture (n.): 1874, from French denture "set of teeth," from Latin dens (genitive dentis, "tooth;" see tooth) + -ure (see -ure). In Middle English, the word meant "an indenture; a zigzag course" (c. 1400). Related: Dentures.
denudation (n.): early 15c., from Middle French dénudation, from Latin denudationem (nominative denudatio), noun of action from past participle stem of denudare (see denude). Figurative use is from 1590s. In geology, from 1811.
denude (v.): early 15c. (implied in denuded), from Middle French dénuder, from Latin denudare "to lay bare, strip; uncover, expose," from de- "away" (see de-) + nudare "to strip," from nudus "naked, bare" (see naked). Related: Denuding.