cosmological (adj.) Look up cosmological at Dictionary.com
1825, from cosmology + -ical.
cosmology (n.) Look up cosmology at Dictionary.com
1650s, from Modern Latin cosmologia, from Greek kosmos (see cosmos) + -logia "discourse" (see -logy). Related: Cosmological; cosmologist.
They cannot scare me with their empty spaces
Between stars--on stars where no human race is.
I have it in me so much nearer home
To scare myself with my own desert places.

[Robert Frost, from "Desert Places," 1936]
cosmonaut (n.) Look up cosmonaut at Dictionary.com
1959, Englishing of Russian kosmonavt, ultimately from Greek kosmos (see cosmos) + nautes "sailor" (see naval).
cosmopolitan (adj.) Look up cosmopolitan at Dictionary.com
1844, from cosmopolite "citizen of the world" (q.v.) on model of metropolitan. The U.S. women's magazine of the same name was first published in 1886. Cosmopolitanism first recorded 1828.
cosmopolite (n.) Look up cosmopolite at Dictionary.com
late 16c., "man of the world; citizen of the world," from Greek kosmopolites "citizen of the world," from kosmos "world" (see cosmos) + polites "citizen" (see politic). In common use 17c. in a neutral sense; it faded out in 18c. but was revived from c.1800 with a tinge of reproachfulness (opposed to patriot).
cosmos (n.) Look up cosmos at Dictionary.com
c.1200 (but not popular until 1848, as a translation of Humboldt's Kosmos), from Latinized form of Greek kosmos "order, good order, orderly arrangement," a word with several main senses rooted in those notions: The verb kosmein meant generally "to dispose, prepare," but especially "to order and arrange (troops for battle), to set (an army) in array;" also "to establish (a government or regime);" "to deck, adorn, equip, dress" (especially of women). Thus kosmos had an important secondary sense of "ornaments of a woman's dress, decoration" (compare kosmokomes "dressing the hair") as well as "the universe, the world."

Pythagoras is said to have been the first to apply this word to "the universe," perhaps originally meaning "the starry firmament," but later it was extended to the whole physical world, including the earth. For specific reference to "the world of people," the classical phrase was he oikoumene (ge) "the inhabited (earth)." Septuagint uses both kosmos and oikoumene. Kosmos also was used in Christian religious writing with a sense of "worldly life, this world (as opposed to the afterlife)," but the more frequent word for this was aion, literally "lifetime, age."
Cossack (n.) Look up Cossack at Dictionary.com
1590s, from Russian kozak, from Turkish kazak "adventurer, guerilla, nomad," from qaz "to wander." The same Turkic root is the source of the people-name Kazakh and the nation of Kazakhstan.
cosset (v.) Look up cosset at Dictionary.com
1650s, "to fondle, caress, indulge," from a noun (1570s) meaning "lamb brought up as a pet" (applied to persons from 1590s), perhaps from Old English cot-sæta "one who dwells in a cot." Related: Coseted; coseting. Compare German Hauslamm, Italian casiccio.
cost (n.) Look up cost at Dictionary.com
c.1200, from Old French cost (12c., Modern French coût) "cost, outlay, expenditure; hardship, trouble," from Vulgar Latin *costare, from Latin constare, literally "to stand at" (or with), with a wide range of figurative senses including "to cost." The idiom is the same one used in Modern English when someone says something "stands at X dollars" to mean it sells for X dollars. The Latin word is from com- "with" (see com-) + stare "to stand," from PIE root *sta- "to stand" (see stet).
cost (v.) Look up cost at Dictionary.com
late 14c., from Old French coster (Modern French coûter) "to cost," from cost (see cost (n.)).
cost-effective (adj.) Look up cost-effective at Dictionary.com
also cost effective, 1967, from cost (n.) + effective.
costa (n.) Look up costa at Dictionary.com
Spanish costa "coast," from same Latin source as English coast (n.). Used in Britain from 1960s in jocular formations (costa geriatrica, costa del crime, etc.) in imitation of the names of Spanish tourist destinations.
costal (adj.) Look up costal at Dictionary.com
"pertaining to the ribs," 1630s, from French costal (16c.), from Medieval Latin costalis, from costa "a rib" (see coast (n.)).
costard (n.) Look up costard at Dictionary.com
late 13c., coster, perhaps from Anglo-French or Old French coste "rib" (from Latin costa "a rib;" see coast (n.)). A kind of large apple with prominent "ribs," i.e. one having a shape more like a green pepper than a plain, round apple. Also applied derisively to "the head." Common 14c.-17c. but limited to fruit-growers afterward.
costermonger (n.) Look up costermonger at Dictionary.com
1510s, "itinerant apple-seller" from coster (see costard) + monger. Sense extended from "apple-seller" to any salesman who plied his wares from a street-cart. Contemptuous use is from Shakespeare ("2 Henry IV"), but reason is unclear.
costive (adj.) Look up costive at Dictionary.com
c.1400, from Middle French costivé, from Latin constipatus, past participle of constipare (see constipation).
costly (adj.) Look up costly at Dictionary.com
late 14c., from cost + -ly (1). Earlier formation with the same sense were costful (mid-13c.), costious (mid-14c.).
costume (n.) Look up costume at Dictionary.com
1715, "style of dress," an art term, from French costume (17c.), from Italian costume "fashion, habit," from Latin consuetudinem (nominative consuetudo) "custom, habit, usage." Essentially the same word as custom but arriving by a different etymology. From "customary clothes of the particular period in which the scene is laid," meaning broadened by 1818 to "any defined mode of dress." Costume jewelry is first attested 1933.
costume (v.) Look up costume at Dictionary.com
1823, from costume (n.). Related: Costumed; costuming.
cosy (adj.) Look up cosy at Dictionary.com
chiefly British form of cozy.
cot (n.1) Look up cot at Dictionary.com
"small bed," 1630s, from Hindi khat "couch, hammock," from Sanskrit khatva, probably from a Dravidian source (compare Tamil kattil "bedstead").
cot (n.2) Look up cot at Dictionary.com
"hut, cottage;" see cote.
cotangent (n.) Look up cotangent at Dictionary.com
from co. tangent, abbreviation of complement + tangent (n.).
cote (n.) Look up cote at Dictionary.com
Old English cote, fem. of cot (plural cotu) "small house, bedchamber, den" (see cottage). Applied to buildings for animals from early 15c.
coterie (n.) Look up coterie at Dictionary.com
1738, from French coterie "circle of acquaintances," originally in Middle French an organization of peasants holding land from a feudal lord (14c.), from cotier "tenant of a cote" (see cottage).
coterminous (adj.) Look up coterminous at Dictionary.com
1630s, malformed in English from co- + terminous (see terminal). Latin purists prefer conterminous.
cotillion (n.) Look up cotillion at Dictionary.com
type of dance, 1766, from French cotillion (15c.), originally "petticoat," a double diminutive of Old French cote "skirt" (see coat (n.)); its application to a kind of dance arose in France and is considered obscure by some linguists, but there are lively turns in the dance that flash the petticoats.

Meaning "formal ball" is 1898, American English, short for cotillion ball. French uses -on (from Latin -onem) to reinforce Latin nouns felt to need more emphatic power (as in poisson from Latin piscis). It also uses -on to form diminutives, often strengthened by the insertion of -ill-, as in the case of this word.
cotquean (n.) Look up cotquean at Dictionary.com
1540s, obsolete, "housewife of a cot," from cot (see cottage) + quean; hence "a vulgar beldam, scold" [OED]; also used contemptuously (by Shakespeare, etc.) of men seen as overly interested in housework.
cottage (n.) Look up cottage at Dictionary.com
late 13c., from Old French cote "hut, cottage" + Anglo-French suffix -age (probably denoting "the entire property attached to a cote"). Old French cot is probably from Old Norse kot "hut," cognate of Old English cot, cote "cottage, hut," from Proto-Germanic *kutan (cognates: Middle Dutch cot, Dutch kot).

Meaning "small country residence" (without suggestion of poverty or tenancy) is from 1765. Modern French cottage is a 19c. reborrowing from English. Cottage industry is attested from 1921. Cottage cheese is attested from 1831, American English, earliest in reference to Philadelphia:
There was a plate of rye-bread, and a plate of wheat, and a basket of crackers; another plate with half a dozen paltry cakes that looked as if they had been bought under the old Court House; some morsels of dried beef on two little tea-cup plates: and a small glass dish of that preparation of curds, which in vulgar language is called smear-case, but whose nom de guerre is cottage-cheese, at least that was the appellation given it by our hostess. ["Miss Leslie," "Country Lodgings," Godey's "Lady's Book," July 1831]
cotter (n.) Look up cotter at Dictionary.com
1640s, perhaps a shortened form of cotterel, a dialectal word for "cotter pin or bolt, bracket to hang a pot over a fire" (1560s), itself of uncertain origin.
cotton (n.) Look up cotton at Dictionary.com
late 13c., from Old French coton (12c.), ultimately (via Provençal, Italian, or Old Spanish) from Arabic qutn, a word perhaps of Egyptian origin. Philip Miller of the Chelsea Physic Garden sent the first cotton seeds to American colony of Georgia in 1732. Also ultimately from the Arabic word, Dutch katoen, German Kattun, Provençal coton, Italian cotone, Spanish algodon, Portuguese algodão. Cotton gin is recorded from 1794 (see gin (n.2)).
cotton (v.) Look up cotton at Dictionary.com
"to get on with" someone (usually with to), 1560s, perhaps from Welsh cytuno "consent, agree." But perhaps also a metaphor from cloth finishing and thus from cotton (n.). Related: Cottoned; cottoning.
cotton-picking (adj.) Look up cotton-picking at Dictionary.com
as a deprecatory term first recorded in a Bugs Bunny cartoon, but a similar noun meaning "contemptible person" dates to around 1919, perhaps with racist overtones that have faded over the years. Before mechanization, cotton picking was the most difficult labor on a cotton plantation.
I drove out to a number of the farms near Denison and found many very young white children working all day in the hot sun picking and dragging sacks of cotton. In one field the labor corps consisted of one woman and six children, one of them 5 years, one 6 years, one 7 years, one 9 years, and two about 11. The father was plowing. The 5 and 6 year olds worked all day as did the rest. The 7-year-old said he picked 50 pounds a day and the 9 year old 75 pounds. (A good picker averages several hundred a day.) School begins late on account of the cotton picking, but the children nearly all prefer school to the picking. Picking hours are long, hot, and deadly monotonous. While the very young children seem to enjoy it, very soon their distaste for it grows into all-absorbing hatred for all work. ["Field Notes of Lewis W. Hine, Child-Labor Conditions in Texas," report to U.S. Congressional Commission on Industrial Relations, 1916]
Cottonian Look up Cottonian at Dictionary.com
library in the British Museum, named for antiquarian Sir Robert Bruce Cotton (1570-1631). He donated some book to the state and his grandson donated the rest. It was badly damaged in a fire in 1731. The surname represents Old English cotum, plural of cot "cottage."
cotyledon (n.) Look up cotyledon at Dictionary.com
from 1540s, in various sense, from Latin cotyledon "pennywort, navelwort," from Greek kotyledon "cup-shaped cavity," from kotyle "hollow thing, small vessel," also the name of a small liquid measure (nearly a half-pint); of uncertain origin. Botanical sense is 1776, from Linnaeus (1751).
couch (v.) Look up couch at Dictionary.com
c.1300, "to overlay with gold, inlay," from Old French couchier "to lay down, place; go to bed, put to bed," from Latin collocare "to lay, place, station, arrange," from com- "together" (see com-) + locare "to place" (see locate). Meaning "to put into words" is from 1520s. Related: Couched; couching. Heraldic couchant ("lying down with the head up") is late 15c., from the French present participle.
couch (n.) Look up couch at Dictionary.com
mid-14c., from Old French couche (12c.) "a bed, lair," from coucher "to lie down," from Latin collocare (see couch (v.)). Traditionally, a couch has the head end only raised, and only half a back; a sofa has both ends raised and a full back; a settee is like a sofa but may be without arms; an ottoman has neither back nor arms, nor has a divan, the distinctive feature of which is that it goes against a wall. Couch potato first recorded 1979.
couch-grass (n.) Look up couch-grass at Dictionary.com
1570s; the first element is a corruption of Old English cwice (see quick).
cougar (n.) Look up cougar at Dictionary.com
1774, from French couguar, Buffon's adaption (influenced by jaguar) of a word the Portuguese picked up in Brazil as çuçuarana, perhaps from Tupi susuarana, from suasu "deer" + rana "false." Another proposed source is Guarani guaçu ara. Evidently the cedillas dropped off the word before Buffon got it. Slang sense of "older woman (35-plus) who seeks younger males as sex partners" is attested by 2002; said in some sources to have originated in Canada, probably from some reference to predatory feline nature.
cough (v.) Look up cough at Dictionary.com
early 14c., coughen, probably in Old English, but not recorded, from Proto-Germanic *kokh- (with the rough "kh" of German or of Scottish loch; cognates: Middle Dutch kochen, Middle High German kuchen). Onomatopoeic. Related: Coughed; coughing. As a noun from c.1300.
could (v.) Look up could at Dictionary.com
Old English cuðe, past tense of cunnan "to be able" (see can (v.1)); ending changed 14c. to standard English -d(e). The excrescent -l- was added 15c.-16c. on model of would, should, where it is historical.
couldn't Look up couldn't at Dictionary.com
by 1670s, contraction of could + not.
coulee (n.) Look up coulee at Dictionary.com
"deep ravine, seasonally flooded," 1804, a North American word, originally in areas explored by French trappers, from French coulée "flow" (17c.), from fem. past participle of couler "to flow," from Latin colare "to filter, strain" (see colander).
coulomb (n.) Look up coulomb at Dictionary.com
1881, named for French chemist Charles-Augustin de Coulomb (1736-1806), who devised a method of measuring electrical quantity. It is the quantity of electricity conveyed in 1 second by a current of 1 ampere. The name is a French form of Columbus.
coulrophobia (n.) Look up coulrophobia at Dictionary.com
"morbid fear of clowns," by 2001 (said in Web sites to date from 1990s or even 1980s), a popular term, not from psychology, possibly facetious, though the phenomenon is real enough; said to be built from Greek kolon "limb," with some supposed sense of "stilt-walker," hence "clown" + -phobia.

Ancient Greek words for "clown" were sklêro-paiktês, from paizein "to play (like a child);" or deikeliktas; other classical words used for theatrical clowns were related to "rustic," "peasant" (compare Latin fossor "clown," literally "laborer, digger," related to fossil).

The whole creation looks suspiciously like the sort of thing idle pseudo-intellectuals invent on the Internet and which every smarty-pants takes up thereafter; perhaps it is a mangling of Modern Greek klooun "clown," which is the English word borrowed into Greek.
coulter (n.) Look up coulter at Dictionary.com
Old English culter, from Latin culter "a knife, iron blade in a plowshare," from PIE root *(s)kel- "to cut" (see scale (n.1)). As a surname (13c.), probably from Coulter in Lancashire.
Coumadin (n.) Look up Coumadin at Dictionary.com
by 1953, name for human anti-coagulant use of the rat poison warfarin sodium, abstracted from the chemical name, 3-(α-acetonylbenzyl)-4-hydroxycoumarin; earlier known as Dicoumarol, it attained publicity when it was used in 1955 to treat U.S. President Dwight Eisenhower after a heart attack. The coumarin element (1830) is from French coumarine, from coumarou, the native name in Guyana of the tonquin bean, one source of the substance.
council (n.) Look up council at Dictionary.com
early 12c., from Anglo-French cuncile, from Old North French concilie (Old French concile, 12c.) "assembly; council meeting; body of counsellors," from Latin concilium "group of people, meeting," from com- "together" (see com-) + calare "to call" (see claim (v.)). Tendency to confuse it in form and meaning with counsel has been consistent since 16c.
councillor (n.) Look up councillor at Dictionary.com
late 14c., alteration of counsellor by assimilation to council.
councilor (n.) Look up councilor at Dictionary.com
see councillor.