Online Etymology Dictionary

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.
crabbed (adj.): late 14c., literally "resembling a crab," in reference to crookedness, from crab (n.1). Of taste "bitter, harsh," late 14c., from crab (n.2). Meaning "peevish" is attested from 1560s, in reference to a crab's combative disposition.
crabby (adj.): 1520s, in now-obsolete sense "crooked, gnarled, rough," from extended sense of crab (n.1) + -y (2). Meaning "disagreeable, sour, peevish" is attested from 1776, American English. Both senses were found earlier in crabbed.
crabgrass (n.): c.1600, from crab (n.1) + grass. Originally a marine grass of salt marshes; modern meaning is from 1743. Perhaps partly for its crooked form.
crack (v.): Old English cracian "make a sharp noise," from Proto-Germanic *krakojan (cf. Middle Dutch craken, Dutch kraken, German krachen), probably imitative. Related: Cracked; cracking. To crack a smile is from 1840s; to crack the whip in the figurative sense is from 1940s.
crack (n.): "split, opening," 14c., from crack (v.). Meaning "try, attempt" first attested 1836, probably a hunting metaphor, from slang sense of "fire a gun." Meaning "rock cocaine" is first attested 1985. The superstition that it is bad luck to step on sidewalk cracks has been traced to c.1890. Adjectival meaning in "top-notch, superior" is slang from 1793 (e.g. a crack shot).
crackdown: also crack down; 1935 (n.), 1940 (v.), from verbal phrase, from crack (v.) + down (adv.).
cracked (adj.): mid-15c., past participle adjective from crack (v). Meaning "mentally unsound" is 17c. (cf. crack-brain "crazy fellow"). The equivalent Greek word was used in this sense by Aristophanes.
cracker (n.1): mid-15c., "hard wafer," but the specific application to a thin, crisp biscuit is 1739; agent noun from crack (v.). Cracker-barrel (adj.) "emblematic of down-home ways and views" is from 1877.
cracker (n.2): Southern U.S. derogatory term for "poor, white trash" (1766), probably from mid-15c. crack "to boast" (e.g. not what it's cracked up to be), originally a Scottish word. Cf. Latin crepare "to rattle, crack, creak," with a secondary figurative sense of "boast of, prattle, make ado about."
I should explain to your Lordship what is meant by crackers; a name they have got from being great boasters; they are a lawless set of rascalls on the frontiers of Virginia, Maryland, the Carolinas and Georgia, who often change their places of abode. [1766, G. Cochrane]
But DARE compares corn-cracker "poor white farmer" (1835, U.S. Midwest colloquial). Especially of Georgians by 1808, though often extended to residents of northern Florida. Another name in mid-19c. use was sand-hiller "poor white in Georgia or South Carolina."
cracker-jack (n.): also crackerjack, "something excellent," 1895, U.S. colloquialism, apparently a fanciful construction. The caramel-coated popcorn-and-peanuts confection was said to have been introduced at the World's Columbian Exposition (1893). Supposedly a salesman gave it the name when he tasted some and said, "That's a cracker-jack," using the then-popular expression. The name was trademarked 1896. The "Prize in Every Box" was introduced 1912.
crackhead (n.): slang, "crack cocaine addict," by 1986, from crack (n.) in the drug slang sense + head (n.). In earlier slang, crack-headed meant "crazy" (1796), from the literal sense of crack.
cracking (adj.): "excellent," colloquial from 1830s, from present participle of crack (v.).
crackle (v.): mid-15c., crackelen, frequentative of cracken "to crack" (see crack (v.)). Related: Crackled; crackling. The noun is recorded from 1833.
crackpot (n.): "mentally unbalanced person," by 1900, probably from crack + pot (n.1) in a slang sense of "head." Cf. crack-brain "crazy fellow" (late 16c.). Earlier it was used in a slang sense "a small-time big-shot" (1883), and by medical doctors in reference to a "metallic chinking sometimes heard when percussion is made over a cavity which communicates with a bronchus."
cradle (n.): c.1200, cradel, from Old English cradol "little bed, cot," from Proto-Germanic *kradulas "basket" (cf. Old High German kratto, krezzo "basket," German Krätze "basket carried on the back"). Cat's cradle is from 1768. Cradle-snatching "amorous pursuit of younger person" is 1925, U.S. slang.
cradle (v.): c.1500, from cradle (n.). Related: Cradled; cradling.
craft (n.): Old English cræft, originally "power, physical strength, might," from Proto-Germanic *krab-/*kraf- (cf. Old Frisian kreft, Old High German chraft, German Kraft "strength, skill;" Old Norse kraptr "strength, virtue"). Sense expanded in Old English to include "skill, art, science, talent" (via a notion of "mental power"), which led to the meaning "trade, handicraft, calling." The word still was used for "might, power" in Middle English.

Use for "small boat" is first recorded 1670s, probably from a phrase resembling vessels of small craft and referring either to the trade they did or the seamanship they required, or perhaps it preserves the word in its original sense of "power."
craft (v.): Old English cræftan "to exercise a craft, build," from the same source as craft (n.). Meaning "to make skilfully" is from early 15c., obsolete from 16c., but revived c.1950s, largely in U.S. advertising and commercial senses. Related: Crafted; crafting.
craftsman (n.): mid-14c., craftes man, from genitive of craft (n.) + man (n.1). Written as one word from late 14c. Old English had cræftiga in this sense. Related: Craftsmanship.
crafty (adj.): c.1200, crafti, from Old English cræftig "strong, powerful," later "skillful, ingenious," degenerating by c.1200 to "cunning, sly" (but through 15c. also "skillfully done or made; intelligent, learned; artful, scientific") from craft (n.) + -y (2). Related: Craftily; craftiness.
crag (n.): early 14c.; as a place-name element attested from c.1200, probably from a Celtic source akin to Old Irish crec "rock," and carrac "cliff," Welsh craig "rock, stone," Manx creg.
craggy (adj.): mid-15c.; see crag + -y (2).
cram (v.): Old English crammian "press something into something else," from Proto-Germanic *kram-/*krem- (cf. Old High German krimman "to press, pinch," Old Norse kremja "to squeeze, pinch"), from PIE root *ger- "to gather" (cf. Sanskrit gramah "heap, troop," Old Church Slavonic gramota "heap," Latin gremium "bosom, lap"). Meaning "study intensely for an exam" originally was British student slang first recorded 1803. Related: Crammed; cramming.
cramp (n.1): "muscle contraction," late 14c., from Old French crampe, from a Frankish or other Germanic word (cf. Old High German krapmhe "cramp, spasm," related to kramph "bent, crooked"), from a Proto-Germanic root forming many words for "bent, crooked," including, via French, crampon. Writer's cramp is first attested 1842 as the name of a physical affliction of the hand, in reference to translations of German medical papers (Stromeyer); also known as scrivener's palsy.
cramp (n.2): "metal bar bent at both ends," early 15c., from Middle Dutch crampe or Middle Low German krampe, both from the same Proto-Germanic root that yielded cramp (n.1). Metaphoric sense of "something that confines or hinders" first recorded 1719.
cramp (v.1): "to contract" (of muscles), early 15c., from cramp (n.1). Related: Cramped; cramping.
cramp (v.2): c.1400, "to bend or twist," from cramp (n.2). Later "compress forcibly" (1550s), and, figuratively, "to restrict" (1620s). Related: Cramped; cramping.
cranberry (n.): 1640s, American English adaptation of Low German kraanbere, from kraan "crane" (see crane (n.)) + Middle Low German bere "berry" (see berry). Perhaps so called from a resemblance between the plants' stamens and the beaks of cranes.

German and Dutch settlers in the New World apparently recognized the similarity between the European berries (Vaccinium oxycoccos) and the larger North American variety (V. macrocarpum) and transferred the name. In England, they were marshwhort or fenberries, but the North American berries, and the name, were brought over late 17c. The native Algonquian name for the plant is represented by West Abenaki popokwa.
crane (n.): Old English cran "large wading bird," common Germanic (cf. Old Saxon krano, Old High German krano, German Kranich, and, with unexplained change of consonant, Old Norse trani), from PIE *gere- (cf. Greek geranos, Latin grus, Welsh garan, Lithuanian garnys "heron, stork"), perhaps echoic of its cry. Metaphoric use for "machine with a long arm" is first attested late 13c. (a sense also in equivalent words in German and Greek).
crane (v.): "to stretch (the neck)," 1799, from crane (n.). Related: Craned; craning.
cranial (adj.): 1800, from Modern Latin cranium, from Greek kranion "skull" (see cranium) + -al (1).
cranio-: word-forming element meaning "of the brain," from Latinized comb. form of Greek kranion "skull" (see cranium).
craniotomy (n.): 1855, from cranio- + -tomy.
cranium (n.): 1540s, from Medieval Latin cranium, from Greek kranion "skull, upper part of the head," related to kara (poetic kras) "head," from PIE root *ker- "horn, head" (see horn (n.)). Strictly, the bones which enclose the brain.
crank (n.): Old English *cranc, implied in crancstæf "a weaver's instrument," crencestre "female weaver, spinster," from Proto-Germanic base *krank-, and related to crincan "to bend, yield" (see crinkle, cringe). English retains the literal sense of the ancient root, while German and Dutch krank "sick," formerly "weak, small," is a figurative use.

The sense of "an eccentric person," especially one who is irrationally fixated, is first recorded 1833, said to be from the crank of a barrel organ, which makes it play the same tune over and over; but more likely a back-formation from cranky (q.v.). Meaning "methamphetamine" attested by 1989.
crank (v.): 1590s, "to zig-zag," from crank (n.). Meaning "to turn a crank" is first attested 1908, with reference to automobile engines. Related: Cranked; cranking.
crankshaft (n.): 1854, from crank (v.) + shaft (n.). The basic form of the mechanism appears to date from Roman times.
cranky (adj.): "cross-tempered, irritable," 1807, from crank (n.) + -y (2). The evolution would be from earlier senses of crank, e.g. "a twist or fanciful turn of speech" (1590s); "inaccessible hole or crevice" (1560s). Grose's 1787 "Provincial Glossary" has "Cranky. Ailing sickly from the dutch crank, sick." and identifies it as a Northern word. Related: Crankily; crankiness.
Ben. Dang it, don't you spare him--A cross grain'd cranky toad as ever crawl'd. (etc.) [Richard Cumberland, "Lovers Resolutions," Act I, 1813]
cranny (n.): mid-15c., possibly from a diminutive of Middle French cran "notch, fissure" (14c.), from crener "to notch, split," from Medieval Latin crenare, possibly from Latin cernere "to separate, sift" (see crisis). But OED casts doubt on this derivation.
crap (v.): "defecate," 1846, from one of a cluster of words generally applied to things cast off or discarded (e.g. "weeds growing among corn" (early 15c.), "residue from renderings" (late 15c.), underworld slang for "money" (18c.), and in Shropshire, "dregs of beer or ale"), all probably from Middle English crappe "grain that was trodden underfoot in a barn, chaff" (mid-15c.), from Middle French crape "siftings," from Old French crappe, from Medieval Latin crappa, crapinum "chaff." Related: Crapped; crapping.

Despite folk etymology insistence, not from Thomas Crapper (1837-1910) who was, however, a busy plumber and may have had some minor role in the development of modern toilets. The name Crapper is a northern form of Cropper (attested from 1221), an occupational surname, obviously, but the exact reference is unclear.
crap (n.): "act of defecation," 1898; see crap (v.). Sense of "rubbish, nonsense" also first recorded 1898.
crape (n.): 1630s, Englished spelling of crepe (q.v.).
crappie (n.): type of freshwater fish, 1856, American English, of unknown origin; perhaps from Canadian French dialectal crappé.
crappy (adj.): 1846, from crap (n.) + -y (2). Related: Crappily; crappiness.
craps (n.): 1843, American English, unrelated to the term for excrement, instead it is from Louisiana French craps "the game of hazard," from an 18c. continental French corruption of English crabs, which was 18c. slang for "a throw of two or three" (the lowest throw), which perhaps is from crab (n.2), the sense in crab apple. The 1843 citation (in an anti-gambling publication) calls it "a game lately introduced into New Orleans."