Online Etymology Dictionary

coach (v.): 1610s, "to convey in a coach," from coach (n.). Meaning "to prepare (someone) for an exam" is from 1849. Related: Coached; coaching.
coachman (n.): 1570s, from coach (n.) + man (n.).
coagulant (n.): 1770, from Latin coagulantem (nominative coagulans), present participle of coagulare (see coagulate).
coagulate (v.): early 15c., from Latin coagulatus, past participle of coagulare "to cause to curdle," from cogere "to curdle, collect" (see cogent). Earlier coagule, c.1400, from Middle French coaguler. Related: Coagulated; coagulating.
coagulation (n.): c.1400, from Latin coagulationem (nominative coagulatio), noun of action from past participle stem of coagulare (see coagulate).
coal (n.): Old English col "charcoal, live coal," from Proto-Germanic *kula(n) (cf. Old Frisian kole, Middle Dutch cole, Dutch kool, Old High German chol, German Kohle, Old Norse kol), from PIE root *g(e)u-lo- "live coal" (cf. Irish gual "coal").

Meaning "mineral consisting of fossilized carbon" is from mid-13c. First mentioned (370 B.C.E.) by Theophrastus in his treatise "On Stones" under the name lithos anthrakos (see anthrax). Traditionally good luck, coal was given as a New Year's gift in England, said to guarantee a warm hearth for the coming year. The phrase drag (or rake) over the coals was a reference to the treatment meted out to heretics by Christians. To carry coals "do dirty work," also "submit to insult" is from 1520s. To carry coals to Newcastle (c.1600) Anglicizes Greek glauk eis Athenas "owls to Athens."
coalesce (v.): 1540s, from Latin coalescere "to unite, grow together, become one in growth," from com- "together" (see co-) + alescere "to grow up" (see adolescent). Related: Coalesced; coalescing; coalescence; coalescent.
coalition (n.): 1610s, "the growing together of parts," from French coalition (1540s), from Late Latin coalitus "fellowship," originally past participle of Latin coalescere (see coalesce). First used in a political sense 1715.
coaming (n.): 1610s, nautical, of unknown origin.
coarse (adj.): early 15c., cors "ordinary" (modern spelling is from late 16c.), probably adjectival use of noun cours (see course (n.)), originally referring to rough cloth for ordinary wear. Developed a sense of "rude" c.1500 and "obscene" by 1711. Perhaps related, via metathesis, to French gros, which had a similar sense development. Related: Coarsely; coarseness.
coarsen (v.): 1805, from coarse + -en (2). Related: Coarsened; coarsening.
coast (n.): "margin of the land," early 14c.; earlier "rib as a part of the body" (early 12c.), from Old French coste "rib, side, flank; slope, incline;" later "coast, shore" (12c., Modern French côte), from Latin costa "a rib," perhaps related to a root word for "bone" (cf. Old Church Slavonic kosti "bone," also see osseous).

Latin costa developed a secondary sense in Medieval Latin of "the shore," via notion of the "side" of the land, as well as "side of a hill," and this passed into Romanic (e.g. Italian costa "coast, side," Spanish cuesta "slope," costa "coast"), but only in the Germanic languages that borrowed it is it fully specialized in this sense (e.g. Dutch kust, Swedish kust, German Küste, Danish kyst). French also used this word for "hillside, slope," which led to verb meaning "sled downhill," first attested 1775 in American English. Expression the coast is clear (16c.) is an image of landing on a shore unguarded by enemies.
coast (v.): late 14c., "to skirt, to go around the sides, to go along the border" of something (as a ship does the coastline), from Anglo-French costien, from the French source of coast (n.). The meaning "sled downhill," first attested 1775 in American English, is a separate borrowing. Of motor vehicles, "to move without thrust from the engine," by 1925; figurative use, of persons, "not to exert oneself," by 1934. Related: Coasted; coasting.
coastal (adj.): 1883, from coast (n.) + -al (1). The proper Latin form costal is used only of ribs.
coaster (n.): 1570s, "one who sails along coasts," agent noun from coast (v.) in its original sense "to go around the sides or border" of something. Applied to vessels for such sailing from 1680s. Tabletop drink stand (c.1887), originally "round tray for a decanter," so called from a resemblance to a sled, or because it "coasted" around the perimeter of the table to each guest in turn after dinner.
coastline (n.): 1860, from coast (n.) + line (n.).
coat (n.): early 14c., "outer garment," from Old French cote "coat, robe, tunic, overgarment," from Frankish *kotta "coarse cloth" or some other Germanic source (cf. Old Saxon kot "woolen mantle," Old High German chozza "cloak of coarse wool," German Kotze "a coarse coat"), of unknown origin. Transferred to animal's natural covering late 14c. Extended 1660s to a layer of any substance covering any surface. Spanish, Portuguese cota, Italian cotta are Germanic loan-words.
coat (v.): late 14c., "to provide with a coat," from coat (n.). Meaning "to cover with a substance" is from 1753. Related: Coated; coating.
coat of arms (n.): mid-14c., originally a tunic embroidered with heraldic arms (worn over armor, etc); see from coat (n.) + arm (n.2) and cf. Old French cote a armer. Sense transferred to the heraldic arms themselves by 1560s. Hence turncoat, one who put his coat on inside-out to hide the badge of his loyalty.
coati (n.): Brazilian raccoon, 1670s, from Tupi (Brazil), from cua "belt, cincture" + tim "nose."
coating (n.): "layer over a surface," 1768, verbal noun from coat (v.).
coattails (n.): also coat-tail, c.1600, from coat (n.) + tail (n.). In 17c., to do something on one's own coattail meant "at one's own expense. Meaning "power of one person," especially in politics, is from 1848 (in a Congressional speech by Abraham Lincoln, in reference to Andrew Jackson); expression riding (someone's) coattails into political office is from 1949.
coauthor (n.): also co-author, from co- + author. From 1948 as a verb. Related: Coauthored; coauthoring.
coax (v.): 1580s, originally in slang phrase to make a coax of, from earlier noun coax, cox, cokes "a fool, ninny, simpleton" (1560s); modern spelling is 1706. Origin obscure, perhaps related to cock (n.1). Related: Coaxed; coaxing.
coaxial (adj.): "having a common axis," 1904, as a term in mathematics; coaxial cable is 1934. See co- + axial.
cob (n.): a word or set of identical words with a wide range of meanings, many seeming to derive from notions of "heap, lump, rounded object," also "head" and its metaphoric extensions. With cognates in other Germanic languages; of uncertain origin and development. "The N.E.D. recognizes eight nouns cob, with numerous sub-groups. Like other monosyllables common in the dial[ect] its hist[ory] is inextricable" [Weekley]. In the 2nd print edition, the number stands at 11. Some senses are probably from Old English copp "top, head," others probably from Old Norse kubbi or Low German, all perhaps from a Proto-Germanic base *kubb- "something rounded." Among the earliest attested English senses are "headman, chief," and "male swan," both early 15c., but the surname Cobb (1066) suggests Old English used a form of the word as a nickname for "big, leading man." The "corn shoot" sense is attested by 1680s.
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.): 1680s, "spiral cavity of the inner ear," 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."