Online Etymology Dictionary

cube (v.): 1580s in the mathematical sense; 1947 with meaning "cut in cubes," from cube (n.). The Greek verbal derivatives from the noun all referred to dice-throwing and gambling. Related: Cubed; cubing.
cubic (adj.): 1550s, from Middle French cubique (14c.), from Latin cubicus, from Greek kybikos, from kybos "cube" (see cube (n.)). Related: Cubical.
cubicle (n.): mid-15c., "bedroom," from Latin cubiculum "bedroom," from cubare "to lie down," originally "bend oneself," from PIE root *keu(b)- "to bend, turn." With Latin -clom, suffix denoting place. Obsolete from 16c. but revived 19c. for "dormitory sleeping compartment," sense of "any partitioned space" (such as a library carrel or, later, office work station) is first recorded 1926.
cubism (n.): 1911, from French cubisme, from cube (see cube (n.)), said to have been coined by French art critic Louis Vauxcelles at the 1908 Salon des Indépendants in reference to a work by Georges Braque. Related: Cubist.
cubit (n.): ancient unit of measure based on the forearm from elbow to fingertip, usually from 18 to 22 inches, early 14c., from Latin cubitum "the elbow," from PIE *keu(b)- "to bend." Such a measure, known by a word meaning "forearm" or the like, was known to many peoples (Greek pekhys, Hebrew ammah, English ell).
cuboid (adj.): "cube-like," 1829, a modern coinage; see cube (n.) + -oid.
cucking stool (n.): early 13c., from cuck "to void excrement," from Old Norse kuka "feces" (the chair was sometimes in the form of a close-stool). Also known as trebucket and castigatory, it was used on disorderly women and fraudulent tradesmen, either in the form of public exposure to ridicule or for ducking in a pond.
cuckold (n.): mid-13c., kukewald, from Old French cucuault, from cocu (see cuckoo) + pejorative suffix -ault, of Germanic origin. So called from the female bird's alleged habit of changing mates, or her authentic habit of leaving eggs in another bird's nest.

In Modern French the identity is more obvious: Coucou for the bird and cocu for the betrayed husband. German Hahnrei (13c.), from Low German, is of obscure origin. The second element seems to be connected to words for "ardent," and suggests perhaps "sexually aggressive hen," with transferal to humans, but Kluge suggests rather a connection to words for "capon" and "castrated." Related: Cuckoldry.
cuckold (v.): 1580s, from cuckold (n.). Related: Cuckolded; cuckolding.
cuckoo (n.): mid-13c., from Old French cocu "cuckoo," also "cuckold," echoic of the male bird's mating cry (compare Greek kokkyx, Latin cuculus, Middle Irish cuach, Sanskrit kokilas). Slang adjectival sense of "crazy" is American English, 1918, but noun meaning "stupid person" is recorded by 1580s, perhaps from the bird's unvarying, oft-repeated call. The Old English name was geac, cognate with Old Norse gaukr, source of Scottish and northern English gowk. The Germanic words presumably originally were echoic, too, but had drifted in form. Cuckoo clock is from 1789.
cucumber (n.): late 14c., from Old French cocombre (13c., Modern French concombre), from Latin cucumerem (nominative cucumis), perhaps from a pre-Italic Mediterranean language. The Latin word also is the source of Italian cocomero, Spanish cohombro, Portuguese cogombro. Replaced Old English eorþæppla (plural), literally "earth-apples."

Cowcumber was common form 17c.-18c., and that pronunciation lingered into 19c. Planted as a garden vegetable by 1609 by Jamestown colonists. Phrase cool as a cucumber (c. 1732) embodies ancient folk knowledge confirmed by science in 1970: inside of a field cucumber on a warm day is 20 degrees cooler than the air temperature.
cud (n.): Old English cudu "cud," earlier cwudu, common Germanic (compare Old Norse kvaða "resin," Old High German quiti "glue," German Kitt "putty"); perhaps from PIE root *gwet- "resin, gum."
cuddle (v.): early 16c. (implied in cudlyng), perhaps a variant or frequentative form of obsolete cull, coll "to embrace" (see collar (n.)); or perhaps from Middle English *couthelen, from couth "known," hence "comfortable with." It has a spotty early history and seems to have been a nursery word at first. Related: Cuddled; cuddling.
cuddly (adj.): 1863, from cuddle + -y (2).
cudgel (n.): Old English cycgel "club with rounded head;" perhaps from PIE root *geu- "to curve, bend."
cudgel (v.): "to beat with a cudgel," 1590s, from cudgel (n.). Related: Cudgeled; cudgeling.
cue (n.1): "stage direction," 1550s, from Q, which was used 16c., 17c. in stage plays to indicate actors' entrances, probably as an abbreviation of Latin quando "when" (see quandary) or a similar Latin adverb. Shakespeare's printed texts have it as both Q and cue.
cue (n.2): "billiard stick," 1749, variant of queue (n.). Cue ball first recorded 1881.
cue (v.): 1928, from cue (n.1). Related: Cued, cueing.
cuff (n.): "bottom of a sleeve," mid-14c., cuffe "hand covering, mitten, glove," perhaps somehow from Medieval Latin cuffia "head covering," which is of uncertain origin. Sense of "band around the sleeve" is first attested 1520s; sense of "hem of trousers" is 1911. Off the cuff "extemporaneously" is 1938 American English colloquial, suggesting an actor or speaker reading from notes jotted on his shirt sleeves rather than learned lines. Cuff links is from 1897.
cuff (v.2): "hit," 1520s, of unknown origin, perhaps from Swedish kuffa "to thrust, push." Related: Cuffed; cuffing. As a noun from 1560s.
cuff (v.1): "to put a cuff on," 1690s, from cuff (n.). Related: Cuffed; cuffing.
cui bono: a Latin phrase from Cicero. It means "to whom for a benefit," or "who profits by it?" not "to what good purpose?" as is often erroneously claimed. From cui "to? for whom?," an old form preserved here in the dative form of the interrogative pronoun quis "who?" (see who) + bono "good" (see bene-).
cuirass (n.): "armor for the chest and back," mid-15c., from Middle French cuirasse (15c.), from Late Latin coriacea vestis "garment of leather," from Latin corium "leather, hide" (see corium). Cognate with Italian corazza, Spanish coraza, Portuguese couraça.
cuisine (n.): 1786, from French cuisine "style of cooking," originally "kitchen, cooking, cooked food" (12c.), from Late Latin cocina, earlier coquina "kitchen," from Latin coquere "to cook" (see cook (n.)).
cul-de-sac (n.): 1738, as an anatomical term, from French cul-de-sac, literally "bottom of a sack," from Latin culus "bottom, backside, fundament." For second element, see sack (n.1). Application to streets and alleys is from 1800.
culdee (n.): mid-12c., from Old Irish céle de "anchorite," from cele "associate, companion," sometimes "servant" (compare ceilidh) + de "of God." Perhaps an attempt to translate Servus Dei or some other Latin term for "religious hermit."
culinary (adj.): 1630s, "of the kitchen," from Latin culinarius "pertaining to the kitchen," from culina "kitchen, food" (see kiln). Meaning "of cookery" is from 1650s.
cull (v.): early 14c., "choose, select, pick; collect and gather the best things from a number or quantity," especially with reference to literary selections, from Old French cuiler "collect, gather, pluck, select" (12c., Modern French cueillir), from Latin colligere "gather together, collect," originally "choose, select" (see collect). Meaning "select livestock according to quality" is from 1889; notion of "select and kill (animals)," usually in the name of reducing overpopulation or improving the stock, is from 1934. Related: Culled; culling.
cull (n.): "dupe, saphead," rogues' slang from late 16c., perhaps a shortening of cullion "base fellow," originally "testicle" (from French couillon, from Old French coillon "testicle; worthless fellow, dolt," from Latin coleus, literally "strainer bag;" see cojones), though another theory traces it to Romany (Gypsy) chulai "man." Also sometimes in the form cully, however some authorities assert cully was the canting term for "dupe" and cull was generic "man, fellow," without implication of gullibility. Compare also gullible.
cull (n.): 1610s, "a selection," from cull (v.). From 1791 as "flock animal selected as inferior;" 1958 as "a killing of animals deemed inferior."
cullen: in some uses it represents an Englishing of Cologne, the city in Germany. As a surname it can be this or from Cullen, Banffshire.
culminate (v.): 1640s, from Late Latin culminatus past participle of culminare "to top, to crown," from Latin culmen (genitive culminis) "top, peak, summit, roof, gable," also used figuratively, contraction of columen (see column). Related: Culminated; culminating.
culmination (n.): 1630s, from French culmination, noun of action from past participle stem of Late Latin culminare (see culminate). Originally a term in astronomy/astrology; figurative use is from 1650s.
culottes (n.): "a divided skirt," 1911, from French culotte "breeches" (16c.), a diminutive of cul "bottom, backside, backside, anus," from Latin culus "bottom, fundament." Earlier, in the singular cullote, it was used to mean "knee-breeches" (1842). Por le cul dieu "By God's arse" was an Old French oath.
culpability (n.): 1670s, from Late Latin culpabilitas "guilt, culpability," from Latin culpabilis (see culpable).
culpable (adj.): late 13c., coupable, from Old French coupable (12c., Modern French coupable), from Latin culpabilis "worthy of blame," from culpare "to blame," from culpa "crime, fault, blame, guilt, error." English (and for a time French) restored the first Latin -l- in later Middle Ages.
culprit (n.): 1670s, from Anglo-French cul prit, contraction of Culpable: prest (d'averrer nostre bille) "guilty, ready (to prove our case)," words used by prosecutor in opening a trial. It seems the abbreviation cul. prit was mistaken in English for an address to the defendant.
cult (n.): 1610s, "worship," also "a particular form of worship," from French culte (17c.), from Latin cultus "care, labor; cultivation, culture; worship, reverence," originally "tended, cultivated," past participle of colere "to till" (see colony). Rare after 17c.; revived mid-19c. with reference to ancient or primitive rituals. Meaning "a devotion to a person or thing" is from 1829.
Cult. An organized group of people, religious or not, with whom you disagree. [Rawson]
cultivar (n.): 1923, from culti(vated) var(iety), coined by U.S. horticulturalist Liberty Hyde Bailey (1858-1954) in "Gentes Herbarum."
cultivate (v.): early 17c., from Medieval Latin cultivatus, past participle of cultivare "to cultivate," from Late Latin cultivus "tilled," from Latin cultus (see cult). Figurative sense of "improve by training or education" is from 1680s. Related: Cultivable; cultivated; cultivating.
cultivation (n.): c. 1700, of knowledge, etc., a figurative use, from French cultivation (16c.), noun of action from cultiver, from Latin cultivare "to till" (see cultivate). Meaning "raising of a plant or crop" is from 1719; literal sense of "tilling of the land" is from 1725.
cultivator (n.): 1660s, noun of action (in Latin form) from cultivate. As the name of an agricultural tool, from 1759.
cultural (adj.): 1868, in reference to the raising of plants or animals, from Latin cultura "tillage" (see culture) + -al (1). In reference to the cultivation of the mind, from 1875; hence, "relating to civilization or a civilization." A fertile starter-word among anthropologists and sociologists, for example cultural diffusion, in use by 1912; cultural diversity by 1935; cultural imperialism by 1937; cultural pluralism by 1932; cultural relativism by 1948.
Cultural Revolution: 1966, from Chinese, translation of Wuchan Jieji Wenhua Da Geming "Proletarian Cultural Great Revolution."
culturalization (n.): by 1929; see cultural + -ization.
culturally (adv.): 1889, from cultural + -ly (2).
culture (n.): mid-15c., "the tilling of land," from Middle French culture and directly from Latin cultura "a cultivating, agriculture," figuratively "care, culture, an honoring," from past participle stem of colere "to tend, guard; to till, cultivate" (see colony). The figurative sense of "cultivation through education" is first attested c. 1500. Meaning "the intellectual side of civilization" is from 1805; that of "collective customs and achievements of a people" is from 1867.
For without culture or holiness, which are always the gift of a very few, a man may renounce wealth or any other external thing, but he cannot renounce hatred, envy, jealousy, revenge. Culture is the sanctity of the intellect. [William Butler Yeats]
Slang culture vulture is from 1947. Culture shock first recorded 1940. Ironic or contemptuous spelling kulchur is attested from 1940 (Pound), and compare kultur.
cultured (adj.): 1743 in the literal sense of "cultivated," of land, etc., past participle adjective from culture; meaning "developed under controlled natural conditions" is from 1906, originally of pearls. Meaning "improved by exposure to intellectual culture" is from 1777.
culvert (n.): 1773, origin unknown, perhaps, as Weekley suggests, the name of a long-forgotten engineer or bridge-builder.