Online Etymology Dictionary

cuspid (n.): 1743, from Latin cuspis (genitive cuspidus) "point, pointed end" (see cusp). Of teeth, from 1878. Related: Cuspidate (adj.), attested from 1690s.
cuspidor (n.): 1779, a colonial word, from Portuguese cuspidor "spittoon," from cuspir "to spit," from Latin conspuere "spit on," from com-, intensive prefix (see com-), + spuere "to spit" (see spew (v.)).
cuss (n.): 1775, American English dialectal, "troublesome person or animal," an alteration of curse (n.), or else a shortening of the slang sense of customer.
cuss (v.): "to say bad words," 1815, alteration of curse (v.). Related: Cussed; cussing. To cuss out attested by 1881.
custard (n.): mid-14c., "meat or fruit pie," crustade, from Middle French croustade (Modern French coutarde), from Old Provençal croustado "fruit tart," literally "something covered with crust," from crosta "crust," from Latin crusta (see crust (n.)). Modern meaning is c. 1600. Spelling change perhaps by influence of mustard.
custodial (adj.): 1772, from custody (Latin custodia) + -al (1).
custodian (n.): 1781, from custody (Latin custodia) + -an. As "janitor," by 1944, American English, short for custodian-janitor (by 1899).
custody (n.): mid-15c., from Latin custodia "guarding, watching, keeping," from custos (genitive custodis) "guardian, keeper, protector," from PIE *(s)keu- "to cover, conceal" (see hide (n.1)).
custom (n.): c. 1200, "habitual practice," from Old French costume "custom, habit, practice; clothes, dress" (12c., Modern French coutume), from Vulgar Latin *consuetumen, from Latin consuetudinem (nominative consuetudo) "habit, usage, way, practice, tradition, familiarity," from consuetus, past participle of consuescere "accustom," from com-, intensive prefix (see com-), + suescere "become used to, accustom oneself," related to sui, genitive of suus "oneself," from PIE *swe- "oneself" (see idiom). Replaced Old English þeaw. Sense of a "regular" toll or tax on goods is early 14c. The native word here is toll.
custom (adj.): "made to measure or order," c. 1830, from custom (n.).
customary (adj.): 1520s, from Medieval Latin custumarius, from Latin consuetudinarius, from consuetitudinem (see custom (n.)). Related: Customarily.
customer (n.): late 14c., "customs official;" later "buyer" (early 15c.), from Anglo-French custumer, from Medieval Latin custumarius, from Latin consuetudinarius (see custom (n.)). More generalized meaning "a person with whom one has dealings" emerged 1540s; that of "a person to deal with" (usually with an adjective, tough, etc.) is by 1580s. In Shakespeare, the word also can mean "prostitute."
customise (v.): chiefly British English spelling of customize (q.v.); for spelling, see -ize.
customize (v.): 1934, "to make (something) to a customer's specifications," American English, from custom (adj.) + -ize. Related: Customizable; customization; customized; customizing.
cut (v.): late 13c., possibly Scandinavian, from North Germanic *kut- (source also of Swedish dialectal kuta "to cut," kuta "knife," Old Norse kuti "knife"), or from Old French couteau "knife." Replaced Old English ceorfan (see carve (v.)), sniþan, and scieran (see shear). Meaning "to be absent without excuse" is British university slang from 1794. To cut a pack of cards is from 1590s. Related: Cutting.
cut (n.): 1520s, "gash, incision," from cut (v.); meaning "piece cut off" is from 1590s; sense of "a wounding sarcasm" is from 1560s.
cutaneous (adj.): 1570s, from Medieval Latin cutaneus, from Latin cutis "the skin" (see cuticle).
cute (adj.): 1731, "clever," shortening of acute; informal sense of "pretty" is 1834, American English student slang. Related: Cuteness.
cutesy (adj.): "artificially or annoyingly cute," by 1968, from cute (adj.).
cutey (n.): alternative spelling of cutie.
cuticle (n.): 1610s, from Latin cuticula, diminutive of cutis "skin," from PIE *ku-ti-, from root *(s)keu- "to cover, conceal" (source also of Lithuanian kiautas "husk," Old English hyd "skin, hide;" see hide (n.1)). Specialized sense of "skin at the base of the nail" is from 1907. Related: Cuticular.
cutie (n.): "cute person," originally especially "attractive young woman," 1917, from diminutive of cute.
cutlass (n.): 1590s, from Middle French coutelas (16c.), probably from Italian coltellaccio "large knife" (with augmentative suffix -accio), from coltello "knife," from Latin cultellus "small knife," diminutive of culter "knife, plowshare," from PIE *kel-tro-, from root *(s)kel- "to cut" (see scale (n.1)).
cutler (n.): c. 1400, from Old French coutelier (12c., Modern French coutelier) "knife-maker," from Latin cultellarius, from cultellus "knife" (see cutlass).
cutlery (n.): mid-14c., cutellerie, "art or trade of knife-making," from Old French coutelerie "cutlery, knife-making" (13c., Modern French coutellerie) "cutting utensils," also "knife-making," from coutel "knife," from Latin cultellus (see cutlass). Meaning "knives and forks collectively" is from 1836.
cutlet (n.): 1706, from French côtelette, from Old French costelette "little rib" (14c.), a double diminutive of coste "rib, side," from Latin costa (see coast (n.)); influenced by English cut.
cutoff (n.): 1640s, "act of cutting off," also "portion cut off," from verbal phrase cut off (late 14c.). Of rivers, from 1773; of roads, from 1806; of clothing (adj.), from 1840.
cutout (n.): 1851, from verbal phrase, from cut (v.) + out (adv.).
cutpurse (n.): "one who steals by the method of cutting purses, a common practice when men wore their purses at their girdles" [Johnson], mid-14c., from cut (v.) + purse (n.). The word continued after the method switched to picking pockets.
cutter (n.): late 12c., "one who cuts" in any sense, agent noun from cut (v.). As a type of small, single-masted vessel, from 1762, earlier "boat belonging to a ship of war" (1745), perhaps so called from the notion of "cutting" through the water.
cutthroat (n.): also cut-throat, 1530s, from cut (v.) + throat (n.). As an adjective from 1560s. Of card games from 1823. For construction, compare daredevil.
cutting edge: also cutting-edge, 1825 in the literal sense (often at first with reference to plows); figurative sense is from 1964.
cuttlefish (n.): Old English cudele "the cuttlefish;" first element perhaps related to Middle Low German küdel "container, pocket;" Old Norse koddi "cushion, testicle;" and Old English codd (see cod).
cuz: 17c. as an abbreviation of cousin; 1889 as an attempt to represent the lazy pronunciation of because.
Cuzco: city in Peru, former capital of the Inca Empire, from Quechua (Inca), literally "navel," in a figurative meaning "center" (of the world, as the navel is the center of the body). Other places known as "navel of the world" include Delphi, Jerusalem, Rome, Easter Island, and Mount Kailash in Tibet.
cv (n.): abbreviation of curriculum vitae.
cwm (n.): 1853, from Welsh cwm "coomb" (see coomb).
cyan (n.): 1889, short for cyan blue (1879), from Greek kyanos "dark blue, dark blue enamel, lapis lazuli," probably a non-Indo-European word, but perhaps akin to, or from, Hittite *kuwanna(n)- "copper blue."
cyanide (n.): a salt of hydrocyanic acid, 1826, from cyano- (before vowels cyan-), used in science as a word-forming element for the carbon-nitrogen compound radical, + chemical ending -ide, on analogy of chloride.

Cyano- is from a Latinized form of Greek kyanos "dark blue" (see cyan). The immediate source of its use in science is French cyanogène, the name given to the compound radical by Gay-Lussac. He called it that because it first had been obtained by heating the dye pigment powder known as Prussian blue (see Prussian).
The cyanogen radical was one of the first examples of a 'compound radical' and was of importance in the development of structural chemistry during the next forty years. [Flood, "Origins of Chemical Names"]
cyanosis (n.): "blue disease," the "blue jaundice" of the ancients, 1820, Medical Latin, from Greek kyanosis, from kyanos "dark blue color" (see cyan) + -osis.
cyanotic (adj.): 1833, from comb. form of root of cyanosis + -ic.
cyber: as an element in word formation, ultimately from cybernetics (q.v.). It enjoyed explosive use with the rise of the Internet early 1990s. One researcher (Nagel) counted 104 words formed from it by 1994. Cyberpunk (by 1986) and cyberspace were among the earliest.
Cyber is such a perfect prefix. Because nobody has any idea what it means, it can be grafted onto any old word to make it seem new, cool -- and therefore strange, spooky. ["New York" magazine, Dec. 23, 1996]
As a stand-alone, it is attested by 1998 as short for cybersex (which is attested by 1995).
cybercafe (n.): 1994, from cyber + cafe.
cybernetic (adj.): 1951, back-formation from cybernetics. Greek kybernetikos meant "good at steering."
cybernetics (n.): coined 1948 by U.S. mathematician Norbert Wiener (1894-1964) from Greek kybernetes "steersman" (metaphorically "guide, governor") + -ics; perhaps based on 1830s French cybernétique "the art of governing."
The future offers very little hope for those who expect that our new mechanical slaves will offer us a world in which we may rest from thinking. Help us they may, but at the cost of supreme demands upon our honesty and our intelligence. [Norbert Wiener, "God and Golem, Inc.," 1964]
cyberspace (n.): 1982, often as two words at first, coined by science fiction writer William Gibson (best known for "Neuromancer") and used by him in a short story published in 1982, from cyber- (see cybernetics) + space (n.).
cyborg (n.): 1960, a blend of the first elements of cybernetic and organism.
cycad (n.): 1845, Modern Latin, from Greek kykas, a word found in Theophrastus, but now thought to be a scribal error for koikas "palm trees," accusative plural of koix, a word from an unknown non-Greek language.
cyclamen (n.): 1550s, from Medieval Latin cyclamen, from Latin cyclaminos, from Greek kyklaminos, from kyklos "circle" (see cycle (n.)). So called in reference to the bulbous shape of the root.
cycle (v.): 1842, "revolve in cycles," from cycle (n.). Meaning "to ride a bicycle" is from 1883. Related: Cycled; cycling.