Online Etymology Dictionary

dale (n.): Old English dæl "dale, valley, gorge," from Proto-Germanic *dalan "valley" (cf. Old Saxon, Dutch, Gothic dal, Old Norse dalr, Old High German tal, German Tal "valley"), from PIE *dhel- "a hollow" (cf. Old Church Slavonic dolu "pit," Russian dol "valley"). Preserved from extinction by Norse influence in north of England.
daliance (n.): mid-14c., "confab, chat," from dally + -ance. Probably formed in Anglo-French, but not attested there. Meaning "amorous play, flirtation" is from late 14c.; that of "idle or frivolous activity" is from 1540s.
Dallas: city in Texas, U.S., settled 1841, named 1846 for George M. Dallas (1792-1864), U.S. vice president under Polk (1845-49); the family name (13c.) is from the barony of Dallas (Moray) or means "dweller at the house in the dale."
dally (v.): c.1300, "to talk, converse," possibly from Anglo-French dalier "to amuse oneself," of uncertain origin. Sense of "waste time" emerged by late 14c. Related: Dallied; dallying.
Dalmatia: region along the eastern Adriatic coast in what is now Croatia; perhaps from a derivative of PIE *dhal- "to bloom," in a sense of "young animal," in reference to the mountain pastures.
Dalmatian: 1810, spotted dog, presumably named for Dalmatia, but dog breeders argue over whether there is a Croatian ancestry for the breed, which seems to be represented in Egyptian bas-reliefs and Hellenic friezes. Popular in early 1800s as a carriage dog, to trot alongside carriages and guard them in owner's absence. Even fire departments nowadays tend to spell it *Dalmation.
Dalton: in reference to a system of school education designed by Helen Parkhurst, 1920, from Dalton, Massachusetts, U.S., where it was first adopted. For Daltonism see color blindness.
dam (n.1): "water barrier," early 14c., probably from Old Norse dammr or Middle Dutch dam, both from Proto-Germanic *dammaz (cf. Old Frisian damm, German Damm), of unknown origin.
dam (n.2): "animal mother," c.1300, variant of dame (q.v.), also originally used, like that word, for "lady, mother;" but meanings diverged into separate spellings by 16c.
dam (v.): late 15c., from dam (n.1). Related: Dammed; damming.
damage (n.): late 13c., from Old French damage (12c., Modern French dommage) "loss caused by injury," from dam "damage," from Latin damnum "loss, hurt, damage" (see damn).
damage (v.): early 14c., from Old French damagier, from damage (see damage (n.)). Related: Damaged; damaging.
Damascus: ancient city in Syria, famous in medieval times for silk and steel, mid-13c., from Latin Damascus, from Greek Damaskos, from Semitic (cf. Hebrew Dammeseq, Arabic Dimashq), from a pre-Semitic name of unknown origin. Related: Damascene, from Latin Damascenus "of Damascus."
damask (n.): late 14c., Damaske "cloth from Damascus," the Syrian city.
dame (n.): early 13c., from Old French dame "lady, mistress, wife," from Late Latin domna, from Latin domina "lady, mistress of the house," from Latin domus "house" (see domestic). Legal title for the wife of a knight or baronet. Slang sense of "woman" first attested 1902 in American English.
dammit: representation of the exclamation damn it! as it usually is sounded, attested from 1908.
damn (v.): late 13c., "to condemn," from Old French damner "damn, condemn; convict, blame; injure," derivative of Latin damnare "to adjudge guilty; to doom; to condemn, blame, reject," from noun damnum "damage, hurt, harm; loss, injury; a fine, penalty," possibly from an ancient religious term from PIE *dap- "to apportion in exchange" [see Watkins]. The Latin word evolved a legal meaning of "pronounce judgment upon." Theological sense is first recorded early 14c.; the optative expletive use likely is as old.

Damn and its derivatives generally were avoided in print from 18c. to c.1930s (the famous line in the film version of "Gone with the Wind" was a breakthrough and required much effort by the studio). The noun is recorded from 1610s; to be not worth a damn is from 1817. The adjective is 1775, short for damned; Damn Yankee, characteristic Southern U.S. term for "Northerner," is attested from 1812. Related: Damning.
damnable (adj.): mid-14c., from Old French damnable or directly from Late Latin damnabilis, from Latin damnare (see damn). Related: Damnably.
damnation (n.): c.1300, "condemnation to Hell by God," also "fact of being condemned by judicial sentence," from Old French damnation, from Latin damnationem (nominative damnatio), noun of action from past participle stem of damnare (see damn). As an imprecation, attested from c.1600.
Damnation follows death in other men,
But your damn'd Poet lives and writes agen.
[Pope, letter to Henry Cromwell, 1707 or 1708]
damnedest (adj.): also damndest, originally damnedst, 1830, superlative of damned (see damn).
Damocles: courtier of Dionysius I, tyrant of Syracuse; his name in Greek means literally "fame of the people," from demos, damos "people" (see demotic) + -kles "fame," a common ending in Greek proper names (e.g. Sophocles, Pericles), from PIE *klew-es, from root *kleu- "to hear" (see listen). To teach Damocles how a tyrant lives, Dionysius seated him at a banquet with a sword suspended above his head by a single hair.
damp (n.): early 14c., "a noxious vapor," perhaps in Old English but there is no record of it. If not, probably from Middle Low German damp; ultimately in either case from Proto-Germanic *dampaz (cf. Old High German damph, German Dampf "vapor;" Old Norse dampi "dust"). Sense of "moisture, humidity" is first certainly attested 1706.
damp (adj.): 1580s, "dazed," from damp (n.). Meaning "slightly wet" is from 1706. Related: Dampness.
damp (v.): late 14c., "to suffocate," from damp (n.). Figurative meaning "to deaden (the spirits, etc.)" attested by 1540s. Meaning "to moisten" is recorded from 1670s. Related: Damped; damping.
dampen (v.): 1630s, "to dull or deaden" (of force, enthusiasm, ardor, etc.), from damp (adj.) + -en (1). Meaning "to moisten" is recorded from 1827. Related: Dampened; dampening.
dampener (n.): 1887, agent noun from dampen.
damper (n.): of a piano, 1783; of a chimney, 1788; agent noun from damp (v.). Either or both led to various figurative senses.
damsel (n.): late 12c., from Old French dameisele "woman of noble birth" (Modern French demoiselle "young lady"), modified (by association with dame) from earlier donsele, from Gallo-Romance *domnicella, diminutive of Latin domina "lady" (see dame). Archaic until revived by romantic poets, along with 16c.-17c. variant form damozel.
dan: title of address to members of religious orders, c.1300, from Old French dan (Modern French dom), from Latin dominus "lord" (source of Portuguese don, Spanish don, Italian donno; see don (n.)).
Dan (1): familiar form of masc. proper name Daniel.
Dan (2): name of one of the 12 tribes of ancient Israel or its territory, named for its founder; literally "he who judges," related to Hebrew din "to judge." In the Old Testament, it occupied the northernmost part of Israel, hence its use proverbially for "utmost extremity," e.g. in from Dan to Beersheba (the southernmost region), 1738.
Dana: fem. proper name; in U.S. little used before c.1925, then in top 100 for girls born from 1963 to 1984.
Danaid (n.): in Greek mythology, one of the 50 daughters of Danaus, king of Argos, from Greek Danaides (plural). On command of their father, all (except Hypermnestra) killed their husbands and consequently were condemned to draw water perpetually in bottomless buckets.
dance (v.): c.1300, from Old French dancier (12c., Modern French danser), of unknown origin, perhaps from Low Frankish *dintjan and akin to Old Frisian dintje "tremble, quiver." A word of uncertain origin but which, through French influence in arts and society, has become the primary word for this activity from Spain to Russia (e.g. Italian danzare, Spanish danzar, Rumanian dansa, Swedish dansa, German tanzen).
In part the loanword from French is used mainly with reference to fashionable dancing while the older native word persists in use with reference to folk-dancing, as definitively Russ. pljasat' vs. tancovat' [Buck].
Replaced Old English sealtian, itself a borrowing from Latin saltare "to dance," frequentative of salire "to leap" (see salient; "dance" words frequently are derived from words meaning "jump, leap"). Related: Danced; dancing.
It is strange, and will, I am sure, appear to my readers almost incredible, that as far as I have ever read, there is no reference that can be identified as containing a clear allusion to dancing in any of our really ancient MS. books. [Eugene O'Curry, "On the Manners and Customs of the Ancient Irish," vol. 2, p.406, 1873]
dance (n.): c.1300, from dance (v.).
dancer (n.): mid-15c., agent noun from dance. (Dancere as a surname is attested from early 12c.). Related: Danseuse "female dancer," from French fem. of danseur.
dandelion (n.): early 15c., earlier dent-de-lioun (late 14c.), from Middle French dent de lion, literally "lion's tooth" (from its toothed leaves), translation of Medieval Latin dens leonis. Other folk names, like tell-time refer to the custom of telling the time by blowing the white seed (the number of puffs required to blow them all off supposedly being the number of the hour), or to the plant's more authentic diuretic qualities, preserved in Middle English piss-a-bed and French pissenlit.
dander (n.): 1831, American English, "temper," of unknown origin; perhaps originally from figurative use of West Indies dander, dunder "fermentation of sugar," from Spanish redundar "to overflow," from Latin redundare (see redundant).
dandle (v.): 1520s, of unknown origin. Perhaps somehow felt to be imitative. Cf. Italian dondolare "to dandle, swing," and French dandiner, from Old French dandin "small bell," imitative of its sound. Related: Dandled; dandling.
dandruff (n.): 1540s, first element obscure, second element is Northumbrian or East Anglian dialectal huff, hurf "scab," from Old Norse hrufa, from Proto-Germanic *hreufaz, source of Old English hreofla "leper."
dandy (n.): c.1780, of uncertain origin; it first appeared in a Scottish border ballad:
I've heard my granny crack
O' sixty twa years back
When there were sic a stock of Dandies O
etc. In that region, Dandy is diminutive of Andrew (as it was in Middle English generally). The word was in vogue in London c.1813-1819. His female counterpart was a dandizette (1821) with French-type ending. The adjective dandy first recorded 1792; very popular c.1880-1900. Related: Dandified; dandify.
Dane (n.): "native of Denmark," from Danish Daner (replacing Old English Dene (plural)); used in Old English of Northmen generally. Perhaps ultimately from a source related to Old High German tanar "sand bank," in reference to their homeland; or from Proto-Germanic *den- "low ground," for the same reason.

Applied 1774 to a breed of large dogs. Danegeld not known by that name in Old English, or until 1086, long after the end of the Viking depredations. Supposedly originally a tax to pay for protection from the Northmen (either to outfit defensive armies or to buy peace). Danelaw (c.1050) was the Danish law in force over that large part of England under Viking rule after c.878; the application to the land itself is modern (1837).
dang: 1793, euphemism for damn.
danger (n.): mid-13c., "power of a lord or master, jurisdiction," from Anglo-French daunger, Old French dangier "power, power to harm, mastery, authority, control" (12c., Modern French danger), alteration (due to assoc. with damnum) of dongier, from Vulgar Latin *dominarium "power of a lord," from Latin dominus "lord, master" (see domain).

Modern sense of "risk, peril" (from being in the control of someone or something else) evolved first in French and was in English late 14c. Replaced Old English pleoh; in early Middle English this sense is found in peril.
dangerous (adj.): early 13c., "difficult, arrogant, severe" (the opposite of affable), from Anglo-French dangerous, Old French dangeros (12c., Modern French dangereux), from danger (see danger).

In Chaucer, it means "hard to please, reluctant to give;" sense of "full of danger, risky" is from late 15c. Other words used in this sense included dangersome (1560s), dangerful (1540s). Related: Dangerously.
dangle (v.): 1590s, probably from Scandinavian (cf. Danish dangle, Swedish dangla "to swing about," Norwegian dangla), perhaps via North Frisian dangeln. Related: Dangled; dangling.
Daniel: proper name, Hebrew, literally "God is my judge;" related to Dan, literally "he who judges," the tribe descended from Jacob's son of that name in Old Testament. Consistently in the top 15 names for boys born in the U.S. from 1972 through 2008.
Danielle: fem. proper name, from Daniel. In U.S., little used before c.1940, and in top 20 for girls born from 1984-1994.
Danish: Old English Denisc "people of Denmark" (see Dane); danish pastry is 1934; shortened form danish is from 1963.
dank (adj.): c.1400, earlier as a verb (early 14c.), now obsolete, meaning "to moisten," used of mists, dews, etc. Perhaps from Scandinavian (cf. Swedish dank "moist place," dänka "to moisten") or German (cf. Middle High German damph, Dutch damp "vapor"). Now largely superseded by damp (adj.). Related: Dankness.