Online Etymology Dictionary

cousin (n.): mid-12c., from Old French cosin (12c., Modern French cousin) "nephew, kinsman, cousin," from Latin consobrinus "cousin," originally "mother's sister's son," from com- "together" (see com-) + sobrinus (earlier *sosrinos) "cousin on mother's side," from soror (genitive sororis) "sister."

Italian cugino, Danish kusine, Polish kuzyn also are from French. German vetter is from Old High German fetiro "uncle."

Many IE languages (including Irish, Sanskrit, Slavic, and some of the Germanic tongues) have or had separate words for some or all of the eight possible "cousin" relationships, e.g. Latin, which along with consobrinus had consobrina "mother's sister's daughter," patruelis "father's brother's son," atruelis "mother's brother's son," amitinus "father's sister's son," etc. Old English distinguished fæderan sunu "father's brother's son," modrigan sunu "mother's sister's son," etc.

Words for cousin tend to drift to "nephew" on the notion of "father's nephew." Used familiarly as a term of address since early 15c., especially in Cornwall. Phrase kissing cousin is Southern U.S. expression, 1940s, apparently denoting "those close enough to be kissed in salutation;" Kentish cousin (1796) is an old British term for "distant relative."
couth (adj.): Old English cuðe "known," past participle of cunnan (see can (v.1)), from Proto-Germanic *kunthaz (cf. Old Frisian kuth "known," Old Saxon cuth, Old High German kund, German kund, Gothic kunþs "known").

Died out as such 16c. with the emergence of could, but the old word was reborn 1896, with a new sense of "cultured, refined," as a back-formation from uncouth (q.v.). The Old English word forms the first element in the man's proper name Cuthbert, literally "famous-bright."
couture (n.): 1908, from French couture, literally "dressmaking, sewing," from Old French costure (12c.), from Vulgar Latin *consutura, from past participle of Latin consuere "to sew together," from con- "together" (see com-) + suere "to sew" (see sew). Used as a collective term for "women's fashion designers."
covalent (adj.): 1929, from covalence (1919), from co- + valence.
covariance: 1878, from covariant (1853), from co- + variant.
cove (n.1): early 14c., "den, cave," from Old English cofa "small chamber, cell," from Proto-Germanic *kubon (cf. Old High German kubisi "tent, hut," German Koben "pigsty," Old Norse kofi "hut, shed"). Extension of meaning to "small bay" is 1580s, apparently via Scottish dialectal meaning "small hollow place in coastal rocks" (c.950).
cove (n.2): "fellow, chap," slang from at least 1560s, said to be from Romany (Gypsy) cova "that man."
coven: "a gathering of witches," 1660s, earlier (c.1500) a variant of covent, cuvent early forms of convent. Association with witches arose in Scotland, but not popularized until Sir Walter Scott used it in this sense in "Letters on Demonology and Witchcraft" (1830).
Ther vold meit bot sometymes a Coven .... Ther is threttein persones in ilk Coeven. [Crim. Trials Scot. III 606, 1662]
covenant (n.): c.1300, from Old French covenant "agreement," originally present participle of covenir "agree, meet," from Latin convenire "come together" (see convene). Applied in Scripture to God's arrangements with man as a translation of Latin testamentum, Greek diatheke, both rendering Hebrew berith (though testament also is used for the same word in different places).
covenant (v.): c.1300, from covenant (n.). Related: Covenanted; covenanting. Covenanter (1638) was used especially in reference to Scottish Presbyterians who signed the Solemn League and Covenant (1643) for the defense and furtherance of their cause.
covent (n.): early form of convent (n.) in use to 17c.
Coventry: city in Warwickshire, Old English Couentre (1043) "Cofa's tree," from Old English masc. personal name Cofa (genitive Cofan) + tree (n.). Probably a boundary marker or public assembly place.
cover (v.): mid-12c., from Old French covrir (12c., Modern French couvrir) "to cover, protect, conceal, dissemble," from Late Latin coperire, from Latin cooperire "to cover over, overwhelm, bury," from com-, intensive prefix (see com-), + operire "to close, cover" (see weir). Related: Covered; covering. Military sense is from 1680s; newspaper sense first recorded 1893; use in football dates from 1907. Betting sense is 1857. OF horses, as a euphemism for "copulate" it dates from 1530s. Covered wagon attested from 1745.
cover (n.): early 13c., in compounds, from cover (v.). Meaning "recording of a song already recorded by another" is 1966. Cover girl is U.S. slang from 1915, shortening of magazine-cover girl.
cover-up (n.): also coverup, "means or act of concealing" some event or activity, 1922, from verbal phrase, from cover (v.) + up (adv.).
coverage (n.): mid-15c., "charge for a booth at a fair," from cover + -age. Reintroduced 1912, American English, in insurance.
coverlet (n.): c.1300, perhaps a diminutive of cover (n.), but early form coverlite suggests an unrecorded Old French *covre-lit, from covrir "to cover" + lit "bed" (see litter (n.)).
covert (adj.): c.1300, from Old French covert "hidden, obscure, underhanded," literally "covered," past participle of covrir "to cover" (see cover). Related: Covertly.
coverture (n.): early 13c., earliest reference is to bedcovers, from Old French coverture (12c.) "blanket; roof; concealment," from Latin *coopertura, from past participle stem of cooperire "to cover" (see cover (v.)). Most modern senses had evolved by mid-15c.
covet (v.): mid-13c., from Old French coveitier (12c., Modern French convoiter) "covet, desire, lust after," influenced by con- words), probably ultimately from Latin cupiditas "passionate desire, eagerness, ambition," from cupidus "very desirous," from cupere "long for, desire" (see cupidity). Related: Coveted; coveting.
covetous (adj.): mid-13c., from Old French coveitos (12c., Modern French convoiteux) "desirous, covetous," from Vulgar Latin *cupiditosus, from Latin cupiditas (see covet). Related: Covetously; covetousness.
covey (n.): mid-14c., "brood of partridges," from Middle French covée "brood" (Modern French couvée), from Gallo-Romance *cubata, literally "hatchling," from past participle stem of Latin cubare "to sit, incubate, hatch" (see incubation).
cow (n.): Old English cu "cow," from Proto-Germanic *kwon (cf. Old Frisian ku, Middle Dutch coe, Dutch koe, Old High German kuo, German Kuh, Old Norse kyr, Danish, Swedish ko), earlier *kwom, from PIE *gwous (cf. Sanskrit gaus, Greek bous, Latin bov-, Old Irish bo, Latvian guovs, Armenian gaus "cow," Slovak hovado "ox"), perhaps ultimately imitative of lowing (cf. Sumerian gu, Chinese ngu, ngo "ox"). In Germanic and Celtic, of females only; in most other languages, of either gender. Other "cow" words sometimes are from roots meaning "horn, horned," e.g. Lithuanian karve, Old Church Slavonic krava.
cow (v.): "intimidate," c.1600, probably from Old Norse kuga "oppress," of unknown origin, but perhaps having something to do with cow (n.) on the notion of easily herded. Related: Cowed; cowing.
cowabunga (interj.): 1954, American English, from exclamation of surprise and anger by "Chief Thunderthud" in "The Howdy Doody Show," 1950s children's TV show; used by surfers 1960s as a shout of triumph, and spread worldwide 1990 by use in the TV cartoon "Teenage Mutant Ninja Turtles."
coward (n.): mid-13c., from Old French coart "coward" (no longer the usual word in French, which has now in this sense poltron, from Italian, and lâche), from coe "tail," from Latin coda, popular dialect variant of cauda "tail," of uncertain origin + -ard, an agent noun suffix denoting one that carries on some action or possesses some quality, with derogatory connotation (see -ard).

The word probably reflects an animal metaphoric sense still found in expressions like turning tail and tail between legs. Coart was the name of the hare in Old French versions of "Reynard the Fox." Italian codardo, Spanish cobarde are from French.
The identification of coward & bully has gone so far in the popular consciousness that persons & acts in which no trace of fear is to be found are often called coward(ly) merely because advantage has been taken of superior strength or position .... [Fowler]
As a surname (attested from 1255) it represents Old English cuhyrde "cow-herd." Farmer has coward's castle "a pulpit," "Because a clergyman may deliver himself therefrom without fear of contradiction or argument."
cowardice (n.): c.1300, from Old French coardise (13c.), from coard, coart (see coward) + noun suffix -ise.
Cowardice, as distinguished from panic, is almost always simply a lack of ability to suspend the functioning of the imagination. [Ernest Hemingway, "Men at War," 1942]
cowardly (adj.): 1550s, from coward + -ly (1). The adverb (late 14c.) is much older than the adjective:
Yit had I levir do what I may Than here to dye thus cowerdelye ["Le Morte d'Arthur," c.1450]
An Old English word for "cowardly" was earg, which also meant "slothful." Related: Cowardliness.
cowbell (n.): 1650s, American English, from cow (n.1) + bell (n.).
cowboy (n.): 1725, "boy who tends to cows," from cow (n.) + boy. Sense in Western U.S. is from 1849; in figurative use by 1942 for "brash and reckless young man" (as an adjective meaning "reckless," from 1920s). Cowhand is first attested 1852 in American English (see hand (n.)). Cowpoke (said to be 1881, not in popular use until 1940s) was said to be originally restricted to the cowboys who prodded cattle onto railroad cars with long poles.
cower (v.): c.1300, probably from Middle Low German *kuren "lie in wait" (Modern German kauern), or similar Scandinavian words meaning "to squat" and "to doze" (e.g. Old Norse kura, Danish, Norwegian kure, Swedish kura). Thus unrelated to coward. Related: Cowered; cowering.
cowl (n.): Old English cule, from earlier cugele, from Late Latin cuculla "monk's cowl," variant of Latin cucullus "hood, cowl," of uncertain origin. Cowling is 1917 in the aircraft sense.
cowlick (n.): 1590s, from cow (n.) + lick (n.). Because it looks like a cow licked your head.
coworker (n.): also co-worker, 1640s, from co- + worker (n.).
Cowper's gland (n.): 1738, so called because discovered by anatomist William Cowper (1666-1709); see Cooper.
cowrie (n.): small shell, used as money in parts of Asia, 1660s, from Hindi and Urdu kauri, from Mahrati kavadi, from Sanskrit kaparda, perhaps related to Tamil kotu "shell."
cowslip (n.): Old English cu-slyppe, apparently from cu "cow" (see cow (n.)) + slyppe "slop, slobber, dung."
Cox: surname, from early 16c., earlier Cocks (c.1300), in many cases from cock (n.1), which apparently was used as a personal name in Old English, also as a familiar term for a boy, later used of apprentices, servants, etc. Perhaps in some cases for the sign of an inn. In some cases perhaps from cook (n.), or Welsh coch "red."
coxcomb (n.): 1570s, from cokkes comb (1560s, see cockscomb).
coxswain (n.): early 14c., "officer in charge of a ship's boat and its crew," from cock "ship's boat" (from Old French coque "canoe") + swain "boy," from Old Norse sveinn "boy, servant" (see swain).
coy (adj.): early 14c., "quiet, modest, demure," from Old French coi, earlier quei "quiet, still, placid, gentle," ultimately from Latin quietus "resting, at rest" (see quiet). Meaning "shy" emerged late 14c. Meaning "unwilling to commit" is 1961. Related: Coyly; coyness.
coyote (n.): 1759, American English, from Mexican Spanish coyote, from Nahuatl coyotl.
coz (n.): 1550s, familiar abbreviation of cousin.
coze (v.): to chat, 1828, of uncertain origin; perhaps from French causer "to talk," from Latin causari "to plead, dispute, discuss a question," from causa (see cause (n.)).
cozen (v.): 1560s, of uncertain origin; perhaps from French cousiner "cheat on pretext of being a cousin;" or from Middle English cosyn "fraud, trickery" (mid-15c.), which is perhaps related to Old French coçon "dealer, merchant, trader," from Latin cocionem "horse dealer." Related: Cozened; cozening; cozenage.
cozy (adj.): 1709, colsie, Scottish dialect, perhaps of Scandinavian origin (cf. Norwegian kose seg "be cozy"). In Britain, usually cosy. Related: Cozily; coziness.
cpr: by 1979, abbreviation of cardiopulmonary resuscitation.
cpu: by 1970, abbreviation of central processing unit.
crab (n.1): crustacean, Old English crabba, from a general Germanic root (cf. Dutch krab, Old High German krebiz, German Krabbe, Old Norse krabbi "crab"), related to Low German krabben, Dutch krabelen "to scratch, claw," from PIE root *gerbh- "to scratch, carve" (see carve). The constellation name is attested in English from c.1000; the Crab Nebula (1868), however, is in Taurus, and is so called for its shape. French crabe (13c.) is from Dutch.
crab (n.2): "fruit of the wild apple tree," c.1300, crabbe, perhaps from Scandinavian scrab, of obscure origin (cf. Swedish krabbäpple). The combination of "bad-tempered, combative" and "sour" in the two nouns crab naturally yielded a verb meaning of "to vex, irritate" (c.1400), later "to complain irritably, find fault" (c.1500). The noun meaning "sour person" is from 1570s.