Online Etymology Dictionary

cobalt (n.): 1680s, from German kobold "household goblin," Harz Mountains silver miners' term for rock laced with arsenic and sulfur (so called because it degraded the ore and made the miners ill), from Middle High German kobe "hut, shed" + *holt "goblin," from hold "gracious, friendly," a euphemistic word for a troublesome being. The metallic element was extracted from this rock. It was known to Paracelsus, but discovery is usually credited to the Swede George Brandt (1733), who gave it the name. Extended to a blue color 1835 (a mineral containing it had been used as a blue coloring for glass since 16c.). Cf. nickel.
cobble (n.): "paving stone; worn, rounded stone," c.1600, earlier cobblestone, probably a diminutive of cob in some sense. The verb in this sense is from 1690s. Related: Cobbled; cobbling.
cobble (v.): "to mend clumsily," late 15c., perhaps a back-formation from cobbler (n.1), or from cob, via a notion of lumps. Related: Cobbled; cobbling.
cobbler (n.1): late 13c., cobelere "one who mends shoes," of uncertain origin. It and cobble (v.) "evidently go together etymologically" [OED], but the historical record presents some difficulties. "The cobbler should stick to his last" (ne sutor ultra crepidam) is from the anecdote of Greek painter Apelles.
On one occasion a cobbler noticed a fault in the painting of a shoe, and remarking upon it to a person standing by, passed on. As soon as the man was out of sight Apelles came from his hiding-place, examined the painting, found that the cobbler's criticism was just, and at once corrected the error. ... The cobbler came by again and soon discovered that the fault he had pointed out had been remedied; and, emboldened by the success of his criticism, began to express his opinion pretty freely about the painting of the leg! This was too much for the patience of the artist, who rushed from his hiding place and told the cobbler to stick to his shoes. [William Edward Winks, "Lives of Illustrious Shoemakers," London, 1883]
[The quote is variously reported: Pliny ("Natural History" XXXV.x.36) has ne supra crepidam judicaret, while Valerius Maximus (VIII.xiii.3) gives supra plantam ascendere vetuit.]
cobbler (n.2): "deep-dish fruit pie," 1859, American English, perhaps related to 14c. cobeler "wooden bowl."
cobblestone (n.): late 14c., kobilstane; see cobble (n.) + stone (n.).
COBOL (n.): 1960, U.S. Defense Department acronym, from "Common Business-Oriented Language."
cobra (n.): 1802, short for cobra capello (1670s), from Portuguese cobra de capello "serpent (of the hood)," from Latin colubra "a snake, female serpent" (source of French couleuvre "adder"), of uncertain origin. So called for the expandable loose skin about its neck. The word came to English via Portuguese colonies in India, where the native name is nag (see naga).
cobweb (n.): early 14c., coppewebbe; the first element is Old English -coppe, in atorcoppe "spider," literally "poison-head" (see attercop). Spelling with -b- is from 16c., perhaps from cob. Cob as a stand-alone for "a spider" was an old word nearly dead even in dialects when J.R.R. Tolkien used it in "The Hobbit" (1937).
coca (n.): South American plant, 1570s, from Spanish coca, from Quechua cuca, which is perhaps ultimately from Aymara, a native language of Bolivia.
Coca-Cola: invented 1886 in Atlanta, Georgia, U.S., by druggist Dr. John S. Pemberton. So called because original ingredients were derived from coca leaves and cola nuts. It contained minute amounts of cocaine until 1909.
Drink the brain tonic and intellectual soda fountain beverage Coca-Cola. [Atlanta "Evening Journal," June 30, 1887]
Coca-colanization, also Coca-colonization coined 1950 during an attempt to ban the beverage in France, led by the communist party and the wine-growers.
France's Communist press bristled with warnings against US "Coca-Colonization." Coke salesmen were described as agents of the OSS and the U.S. State Department. "Tremble," roared Vienna's Communist Der Abend, "Coca-Cola is on the march!" [Time Magazine, 1950]
Coca-colonialism attested by 1956.
cocaine (n.): 1874, from Modern Latin cocaine (1856), coined by Albert Niemann of Gottingen University from coca (from Quechua cuca) + chemical suffix -ine (2). A medical coinage, the drug was used 1870s as a local anaesthetic for eye surgery, etc. "It is interesting to note that although cocaine is pronounced as a disyllabic word it is trisyllabic in its formation." [Flood]
cocci (n.): spherical-shaped bacteria, plural of Latin coccus, from Greek kokkos "berry" (see cocco-).
coccidiosis (n.): Modern Latin, from Greek *kokkidion, diminutive of kokkis, diminutive of kokkos "berry" + -osis.
cocco-: word-forming element meaning "berry, seed," or something shaped like them, from Latinized form of Greek kokkos "a grain, a seed," especially "kermes-berry, gall of the kermes oak" (actually an insect), which yields scarlet dye, of unknown origin, perhaps from a non-Greek source.
coccus (n.): 1763 as an insect genus (including the cochineal bug); 1883 as a type of bacterium, from Greek kokkos "grain, seed, berry" (see cocco-).
coccyx (n.): 1610s, from Latin coccyx, from Greek kokkyx "cuckoo" (from kokku, like the bird's English name echoic of its cry), so called by ancient Greek physician Galen because the bone in humans supposedly resembles a cuckoo's beak.
Cochin-china: old name of a region and French colony in southern Vietnam, from French Cochin-China, from Portuguese corruption of Ko-chen, of uncertain meaning; the China added to distinguish it from the town and port of Cochin in southwest India, the name of which is Tamil, perhaps from koncham "little," in reference to the river there.
cochineal (n.): 1580s, from French cochenille (16c.), probably from Spanish cochinilla, from a diminutive of Latin coccinus (adj.) "scarlet-colored," from coccum "berry (actually an insect) yielding scarlet dye" (see kermes). But some sources identify the Spanish source word as cochinilla "wood louse" (a diminutive form related to French cochon "pig").

The insect (Coccus Cacti) lives on the prickly pear cactus in Mexico and Central America and is a relative of the kermes and has similar, but more intense, dying qualities. Aztecs and other Mexican Indians used it as a dyestuff. It first is mentioned in Europe in 1523 in Spanish correspondence to Hernán Cortés in Mexico. Specimens were brought to Spain in the 1520s, and cloth merchants in Antwerp were buying cochineal in insect and powdered form in Spain by the 1540s. It soon superseded the use of kermes as a tinetorial substance. Other species of coccus are useless for dye and considered mere pests, such as the common mealy bug.
Cochise: (c.1815-1874), leader of the Chiricahua Apache people; his name is Athabaskan, perhaps from chizh "firewood" (cf. ko-chizh "his firewood"), or from ch'izhi "the rough one."
cochlea (n.): "spiral cavity of the inner ear," 1680s, from Latin cochlea "snail shell," from Greek kokhlias "snail, screw," etc., from kokhlos "spiral shell," perhaps related to konkhos "mussel, conch."
cock (n.1): "male chicken," Old English cocc "male bird," Old French coc (12c., Modern French coq), Old Norse kokkr, all of echoic origin. Old English cocc was a nickname for "one who strutted like a cock," thus a common term in the Middle Ages for a pert boy, used of scullions, apprentices, servants, etc.

A common personal name till c.1500, it was affixed to Christian names as a pet diminutive, e.g. Wilcox, Hitchcock, etc. Slang sense of "penis" is attested since 1610s (but cf. pillicock "penis," from c.1300); cock-teaser is from 1891. A cocker spaniel (1823) was trained to start woodcocks. Cock-and-bull is first recorded 1620s, perhaps an allusion to Aesop's fables, with their incredible talking animals, or to a particular story, now forgotten. French has parallel expression coq-à-l'âne.
cock (n.2): in various mechanical senses, such as cock of a faucet (early 15c.) is of uncertain connection with cock (n.1), but German has hahn "hen" in many of the same senses. The cock of an old matchlock firearm is 1560s, hence half-cocked "with the cock lifted to the first catch, at which position the trigger does not act" (by 1809).
cock (v.): mid-12c., cocken, "to fight;" 1570s, "to swagger;" seeming contradictory modern senses of "to stand up" (as in cock one's ear), c.1600, and "to bend" (1898) are from the two cock nouns. The first is probably in reference to the posture of the bird's head or tail, the second to the firearm position. To cock ones hat carries the notion of "defiant boastfulness."
cock-a-doodle-doo: 1570s, imitative; cf. French cocorico, German kikeriki, Latin cucurire, Russian kikareku, Vietnamese cuc-cu, Arabic ko-ko, etc.
cockade (n.): 1709, earlier cockard (1650s), from French cocarde (16c.), fem. of cocard (Old French cocart) "foolishly proud, cocky," as a noun, "idiot, fool;" an allusive extension from coq (see cock (n.1)).
Cockaigne (n.): c.1300, from Old French Cocaigne (12c.) "lubberland," imaginary country, abode of luxury and idleness. Of obscure origin, speculation centers on words related to cook (v.) and cake (cf. Middle Dutch kokenje, a child's honey-sweetened treat; also cf. Big Rock Candy Mountain). The German equivalent is Schlaraffenland.
cockamamie (adj.): American English slang word attested by 1946, popularized c.1960, but said to be New York City children's slang from mid-1920s; perhaps an alteration of decalcomania (see decal).
cockatoo (n.): 1610s, from Dutch kaketoe, from Malay kakatua, possibly echoic, or from kakak "elder brother or sister" + tua "old." Also cockatiel (1880), from Dutch diminutive kaketielje (1850), which is perhaps influenced by Portuguese. Spelling influenced by cock (n.1).
cockatrice (n.): late 14c., from Old French cocatriz, altered (by influence of coq) from Late Latin *calcatrix, from Latin calcare "to tread" (from calx (1) "heel"), as translation of Greek ikhneumon, literally "tracker, tracer."

In classical writings, an Egyptian animal of some sort, the mortal enemy of the crocodile, which it tracks down and kills. This vague sense became hopelessly confused in the Christian West, and in England the word ended up applied to the equivalent of the basilisk. A serpent hatched from a cock's egg, it was fabled to kill by its glance and could be slain only by tricking it into seeing its own reflection. Belief in them persisted even among the educated because the word was used in the KJV several times to translate a Hebrew word for "serpent." In heraldry, a beast half cock, half serpent.
cockchaffer (n.): from cock (n.1), in reference to its size, + chaffer.
cockerel (n.): "young cock," mid-15c. (late 12c. as a surname), apparently a diminutive of cock (n.1). Despite the form, no evidence that it is from French.
cockeyed (adj.): 1821, "squint-eyed," perhaps from cock (v.) in some sense + eye (n.). Figurative sense of "absurd, askew, crazy" is from 1896; that of "drunk" is attested from 1926.
cockle (n.1): type of mollusk, early 14c., from Old French coquille (13c.) "scallop, scallop shell; mother of pearl; a kind of hat," altered (by influence of coque "shell") from Vulgar Latin *conchilia, from Latin conchylium "mussel, shellfish," from Greek konkhylion "little shellfish," from konkhe "mussel, conch." Phrase cockles of the heart (1660s) is perhaps from similar shape, or from Latin corculum, diminutive of cor "heart."
cockle (n.2): flowering weed that grows in wheat fields, Old English coccel "darnel," used in Middle English to translate the Bible word now usually given as tares (see tare (n.1)). It is in no other Germanic language and may be from a diminutive of Latin coccus "grain, berry."
cockney (n.): c.1600, usually said to be from rare Middle English cokenei, cokeney "spoiled child, milksop" (late 14c.), originally cokene-ey "cock's egg" (mid-14c.). Most likely disentangling of the etymology is to start from Old English cocena "cock's egg" -- genitive plural of coc "cock" + æg "egg" -- medieval term for "runt of a clutch," extended derisively c.1520s to "town dweller," gradually narrowing thereafter to residents of a particular neighborhood in the East End of London. Liberman, however, disagrees:
[I]n all likelihood, not the etymon of ME cokeney 'milksop, simpleton; effeminate man; Londoner,' which is rather a reshaping of [Old French] acoquiné 'spoiled' (participle). However, this derivation poses some phonetic problems that have not been resolved.
The accent so called from 1890, but the speech peculiarities were noted from 17c. As an adjective in this sense, from 1630s.
cockpit (n.): 1580s, "a pit for fighting cocks," from cock (n.1) + pit (n.1). Used in nautical sense (1706) for midshipmen's compartment below decks; transferred to airplanes (1914) and to cars (1930s).
cockroach (n.): 1620s, folk etymology (as if from cock + roach) of Spanish cucaracha "chafer, beetle," from cuca "kind of caterpillar." Folk etymology also holds that the first element is from caca "excrement."
A certaine India Bug, called by the Spaniards a Cacarootch, the which creeping into Chests they eat and defile with their ill-sented dung [Capt. John Smith, "Virginia," 1624].
cockscomb (n.): c.1400, "comb or crest of a cock," from possessive of cock (n.1) + comb (n.). Meaning "cap worn by a professional fool" is from 1560s; hence "conceited fool" (1560s), a sense passing into the derivative coxcomb. As a plant name, from 1570s.
cocksucker (n.): 1890s, "one who does fellatio" (especially a male homosexual); 1920s as "contemptible person," American English, from cock (n.1) in phallic sense + sucker (n.). Used curiously for aggressively obnoxious men; the ancients would have recoiled at this failure to appreciate the difference between passive and active roles; Catullus, writing of his boss, employs the useful Latin insult irrumator, which means "someone who forces others to give him oral sex," hence "one who treats people with contempt."
cocksure (adj.): 1520s, "certain," from cock (n.1) + sure (adj.). Probably "as assured as a cock." "The word was originally perfectly dignified, and habitually used in the most solemn connexions" [OED].
cocktail (n.): first attested 1806; H.L. Mencken lists seven versions of its origin, perhaps the most persuasive is French coquetier "egg-cup" (15c.; in English cocktay). In New Orleans, c.1795, Antoine Amédée Peychaud, an apothecary (and inventor of Peychaud bitters) held Masonic social gatherings at his pharmacy, where he mixed brandy toddies with his own bitters and served them in an egg-cup. On this theory, the drink took the name of the cup. Used from 1920s of any mix of substances (e.g. fruit, Molotov). Cocktail party first attested 1928.
cocky (adj.): "arrogantly pert," 1768; originally "lecherous" (1540s); from cock (n.1) + -y (2). Related: Cockiness.
coco (n.): "palm tree," mid-16c., from Spanish and Portuguese coco "grinning face," on resemblance of the three holes at the base of the shell to a human face. The earlier word for it was the Latinized form cocus, which sometimes was anglicized as cocos.
cocoa (n.): powder from cacao seeds, 1707, corruption (by influence of coco) of cacao. The printing of Johnson's dictionary ran together the entries for coco and cocoa, fostering a confusion that never has been undone.
coconut (n.): 1610s, from coco + nut. Meaning "the head" is slang from 1834.
cocoon (n.): 1690s, from Middle French coucon (16c., Modern French cocon), from coque "clam shell, egg shell, nut shell" (7c.), from Old French coque "shell," from Latin coccum "berry," from Greek kokkos "berry, seed" (see cocco-). The sense of "one's interior comfort place" is from 1986. Also see -oon.
cocoon (v.): 1986, "to stay inside and be inactive," from coccoon (n.).
A lady with an enchanting name, Faith Popcorn, has identified a menacing new American behavior that she gives the sweet name of 'cocooning.' It threatens the nation's pursuit of happiness, sometimes called the economy. [George Will, April 1987]
Related: Cocooned; cocooning.
cocotte (n.): type of cooking vessel, 1907, from French cocotte "saucepan" (19c.), a diminutive from cocasse, ultimately from Latin cucama. Sense of "prostitute," 1867, is from French cocotte, originally a child's name for "little hen" (18c.), hence "sweetie, darling."
cod (n.): large sea fish, mid-14c. (late 13c. in a surname, Thomas cotfich), of unknown origin; despite similarity of form it has no conclusive connection to the widespread Germanic word for "bag" (e.g. Old English codd, preserved in codpiece). Cod-liver oil known since at least 1610s, was recommended medicinally since 1783, but not popular as a remedy until after 1825.