Online Etymology Dictionary

Colosseum (n.): 1560s, Medieval Latin name for the classical Amphitheatrum Flavium (begun c.70 C.E.), noun use of neuter of adjective colosseus "gigantic;" perhaps a reference to the colossal statue of Nero that long stood nearby (see colossus).
colossus (n.): "gigantic statue," late 14c., from Latin colossus "a statue larger than life," from Greek kolossos "gigantic statue," of unknown origin, used by Herodotus of giant Egyptian statues, and used by Romans of the bronze Apollo at the entrance to the harbor of Rhodes. Figurative sense of "any thing of awesome greatness or vastness" is from 1794.
colostomy (n.): 1888, from colon (n.2) + Modern Latin -stoma "opening, orifice," from Greek stoma "opening, mouth" (see stoma).
colostrum (n.): 1570s, from Latin colostrum "first milk from an animal," of unknown origin.
colour: chiefly British English spelling of color (q.v.); for ending see -or. Related: Coloured; colouring; colourful; colours.
colposcopy (n.): 1940, from colpo-, Latinized comb. form of Greek kolpos "womb" (used from c.1900 in medical compounds in sense "vagina;" see gulf (n.)) + -oscopy (see -scope).
colt (n.): Old English colt "colt," originally "young ass," in Biblical translations also used for "young camel," perhaps from Proto-Germanic *kultaz (cf. Swedish dialectal kult "young boar, piglet; boy," Danish kuld "offspring, brood") and akin to child. Applied to persons from early 13c.
COLT'S TOOTH An old fellow who marries, or keeps a young girl, is ſaid to have a colt's tooth in his head. ["Classical Dictionary of the Vulgar Tongue," 1796]
Colt (n.): type of revolver, 1838, originally the manufacture of U.S. gunsmith Samuel Colt (1814-1862).
coltish (adj.): late 14c., "wild, frisky," also in early use "lustful, lewd," from colt + -ish. Lit. sense of "pertaining to a colt" is recorded from 1540s.
columbarium (n.): "subterranean sepulchre in ancient Roman places with niches for urns holding remains," neuter of Latin columbarius, "dove-cote" (so called from resemblance), literally "pertaining to doves;" from columba "dove." Literal sense of "dove-cote" is attested in English from 1881.
Columbia: poetic name for United States of America, earlier for the British colonies there, 1730s, also the nation's female personification, from name of Christopher Columbus (also see Colombia) with Latin "country" ending -ia. A popular name for places and institutions in the U.S. in the post-Revolutionary years, when former tributes to king and crown were out of fashion: e.g. Columbia University (New York, U.S.) founded in 1754 as King's College; re-named 1784. Also District of Columbia (1791, as Territory of Columbia); "Hail, Columbia" (Joseph Hopkinson, 1798), Barlow's "Columbiad" (1809).
columbine (n.): c.1300, from Old French columbine "columbine," or directly from Medieval Latin columbina, from Late Latin columbina "verbena," fem. of Latin columbinus, literally "dove-like," from columba "dove." The inverted flower supposedly resembles a cluster of five doves. Also a fem. proper name; in Italian comedy, the name of the mistress of Harlequin.
Columbus: his name is Latinized from his native Italian Cristoforo Colombo, in Spanish Christobal Colon.
America was discovered accidentally by a great seaman who was looking for something else, and most of the exploration for the next fifty years was done in the hope of getting through or around it. [S.E. Morison, "The Oxford History of the United States," 1965]
column (n.): mid-15c., "vertical division of a page," also "a pillar, post," from Old French colombe (12c., Modern French colonne "column, pillar"), from Latin columna "pillar," collateral form of columen "top, summit," from PIE root *kel- "to project" (see hill). Sense of "matter written for a newspaper" dates from 1785.
columnar (adj.): 1728, from Late Latin columnaris "rising in the form of a pillar," from columna "column" (see column).
columnist (n.): 1920, from column in the newspaper sense + -ist.
com-: word-forming element usually meaning "with, together," from Latin com, archaic form of classical Latin cum "together, together with, in combination," from PIE *kom- "beside, near, by, with" (cf. Old English ge-, German ge-). The prefix in Latin sometimes was used as an intensive.

Before vowels and aspirates, reduced to co-; before -g-, assimilated to cog- or con-; before -l-, assimilated to col-; before -r-, assimilated to cor-; before -c-, -d-, -j-, -n-, -q-, -s-, -t-, -v- assimilated to con-.
coma (n.1): state of prolonged unconsciousness, 1640s, from Latinized form of Greek koma (genitive komatos) "deep sleep," of uncertain origin.
coma (n.2): "head of a comet," 1765, from Latin coma, from Greek kome "hair of the head," of unknown origin. Earlier in English as a botanical term for a tuft of hairs (1660s).
Comanche (n.): 1819, from Spanish, from a Shoshonean language, e.g. Ute kimánci "enemy, foreigner." Comanchero was a 19c. name given to Hispanic and American traders who dealt with the Comanches.
comatose (adj.): 1755, from Latinized form of Greek komat-, comb. form of koma (genitive komatos; see coma) + -ose (1). Perhaps immediately from French comateux. Transferred sense of "lethargic" is from 1828.
comb (n.): Old English camb "comb, crest, honeycomb" (later Anglian comb), from West Germanic *kambaz (cf. Old Saxon and Old High German camb, German Kamm, Middle Dutch cam, Dutch kam, Old Norse kambr), literally "toothed object," from PIE *gombhos, from root *gembh- "to bite, tooth" (cf. Greek gomphos "a molar tooth," Sanskrit gambha-s "tooth").
comb (v.): late 14c. (implied in past participle kombid), verb derived from comb (n.); replacing the former verb, Old English cemban, which however survives in unkempt. Related: Combed; combing.
combat (v.): 1560s, from Middle French combat (16c.), from Old French combattre (12c.), from Late Latin combattere, from Latin com- "with" (each other) (see com-) + battuere "to beat, fight" (see batter (v.)). Related: Combated; combating; combatted; combatting.
combat (n.): 1560s, from Middle French combat (16c.), from combattre (see combat (v.)).
combatant: mid-15c. (adj.), late 15c. (n.), from Old French combatant (Modern French combattant) "skilled at fighting, warlike" (also used as a noun in Old French), present participle adjective of combattre (see combat (v.)).
combative (adj.): 1819, from combat + -ive. In 1820s-30s, much associated with phrenology. Related: Combatively; combativeness (1815).
comber (n.): c.1200, "one who cards wool," agent noun from comb (v.).
combination (n.): late 14c., combinacyoun, from Old French combination (14c., Modern French combinaison), from Late Latin combinationem (nominative combinatio) "a joining two by two," noun of action from past participle stem of combinare (see combine (v.)).
combine (n.): "machine that cuts, threshes and cleans grain" (short for combine harvester), 1857, from combine (v.).
combine (v.): early 15c., from Middle French combiner (14c.), from Late Latin combinare "to unite, yoke together," from Latin com- "together" (see com-) + bini "two by two," adverb from bi- "twice" (see binary). Related: Combinative; combined; combining.
combo (n.): 1929, U.S. slang, originally in entertainment (jazz groups, dance teams), short for combination.
combust: late 14c. as an adjective, "burnt," from Old French combust (14c.), from Latin combustus, past participle of combuere "to burn up, consume" (see combustion). Also an astrological term for planets when near the sun. The verb is attested from late 15c. Related: Combusted; combusting.
combustible (adj.): 1520s, from Middle French combustible, or directly from Late Latin combustibilis, from Latin combustus, past participle of combuere "to burn up, consume" (see combustion). Figurative sense is from 1640s; as a noun, from 1680s. Related: Combustibility (late 15c.).
combustion (n.): early 15c., from Old French combustion (13c.), from Latin combustionem (nominative combustio) "a burning," noun of action from past participle stem of Latin comburere "to burn up, consume," from com-, intensive prefix (see com-), + *burere, faulty separation of amburere "to burn around," actually ambi-urere, from urere "to burn, singe," from PIE root *eus- "to burn" (see ember).
come (v.): Old English cuman "come, approach, land; come to oneself, recover; arrive; assemble" (class IV strong verb; past tense cuom, com, past participle cumen), from Proto-Germanic *kwem- (cf. Old Saxon cuman, Old Frisian kuma, Middle Dutch comen, Dutch komen, Old High German queman, German kommen, Old Norse koma, Gothic qiman), from PIE root *gwa-, *gwem- "to go, come" (cf. Sanskrit gamati "he goes," Avestan jamaiti "goes," Tocharian kakmu "come," Lithuanian gemu "to be born," Greek bainein "to go, walk, step," Latin venire "to come").

The substitution of Middle English -o- for Old English -u- before -m-, -n-, or -r- was a scribal habit before minims to avoid misreading the letters in the old style handwriting, which jammed letters. The practice similarly transformed some, monk, tongue, worm. Modern past tense form came is Middle English, probably from Old Norse kvam, replacing Old English cuom.

Remarkably productive with prepositions (NTC's "Dictionary of Phrasal Verbs" lists 198 combinations); consider the varied senses in come to "regain consciousness," come over "possess" (as an emotion), come at "attack," come on (interj.) "be serious," and come off "occur." For sexual senses, see cum.
comeback (n.): "verbal retort," 1889, from come + back (adj.). Meaning "recovery, return to former position or condition after retirement or loss" is attested from 1908, American English.
comedian (n.): 1580s, "comic poet," later (c.1600) "stage actor in comedies," also, generally, "actor," from Middle French comédien, from comédie (see comedy). Meaning "professional joke-teller, etc." is from 1898.
comedic (adj.): 1630s, from Latin comoedicus, from Greek komoidikos "pertaining to comedy," from komoidia (see comedy).
comedienne (n.): 1860, from French comédienne, fem. of comédien (see comedian).
comedo (n.): "blackhead," etc., 1866, from Latin comedo "glutton," from comedere "to eat up" (see comestible). A name formerly given to worms that devour the body; transferred in medical use to secretions that resemble them.
comedy (n.): late 14c., from Old French comedie (14c., "a poem," not in the theatrical sense), from Latin comoedia, from Greek komoidia "a comedy, amusing spectacle," probably from komodios "actor or singer in the revels," from komos "revel, carousal, merry-making, festival," + aoidos "singer, poet," from aeidein "to sing," related to oide (see ode).
The passage on the nature of comedy in the Poetic of Aristotle is unfortunately lost, but if we can trust stray hints on the subject, his definition of comedy (which applied mainly to Menander) ran parallel to that of tragedy, and described the art as a purification of certain affections of our nature, not by terror and pity, but by laughter and ridicule. [Rev. J.P. Mahaffy, "A History of Classical Greek Literature," London, 1895]
The classical sense of the word, then, was "amusing play or performance," which is similar to the modern one, but in the Middle Ages the word came to mean poems and stories generally (albeit ones with happy endings), and the earliest English sense is "narrative poem" (e.g. Dante's "Commedia"). Generalized sense of "quality of being amusing" dates from 1877.
Comedy aims at entertaining by the fidelity with which it presents life as we know it, farce at raising laughter by the outrageous absurdity of the situation or characters exhibited, & burlesque at tickling the fancy of the audience by caricaturing plays or actors with whose style it is familiar. [Fowler]
comely (adj.): "beautiful, handsome," c.1400, probably from Old English cymlic "lovely, splendid, finely made," from cyme "exquisite, glorious, delicate," from West Germanic *kumi- "delicate, feeble" (cf. Old High German chumo "with difficulty," chumig "weak, delicate;" German kaum "hardly, scarcely"). Or perhaps the modern word is from Middle English bicumelic (c.1200) "suitable, exquisite," literally "becomely" (cf. becoming).
comer (n.): "visitor," mid-14c., agent noun from come. Meaning "one showing promise" is attested from 1879. Phrase all comers "everyone who chooses to come" is recorded from 1560s.
comestible (n.): 1837, "article of food," from French comestible (14c.), from Late Latin comestibilis, from Latin comestus, past participle of comedere "eat up, consume," from com- "thoroughly" (see com-) + edere "to eat" (see edible). It was attested earlier as an adjective (late 15c.) meaning "fit to eat" but seems to have fallen from use 17c., and the word was reintroduced from French.
comet (n.): c.1200, from Old French comete (12c., Modern French comète), from Latin cometa, from Greek (aster) kometes, literally "long-haired (star)," from kome "hair of the head" (cf. koman "let the hair grow long"), of unknown origin. So called from resemblance of a comet's tail to streaming hair.
cometh (v.): obsolete or poetic 2nd and 3rd person singular of come, from Old English cymeð.
comeuppance (n.): also comeupance, 1859, presumably rooted in verbal phrase come up "present oneself for judgment before a tribunal" + -ance.
comfit (n.): early 14c., "sugarplum," from Old French confit "preserved fruit," from Latin confectum, from confectionem (see confection).
comfort (v.): late 13c., conforten "to cheer up, console," from Old French conforter "to comfort, to solace; to help, strengthen," from Late Latin confortare "to strengthen much" (used in Vulgate), from Latin com-, intensive prefix (see com-), + fortis "strong" (see fort). Change of -n- to -m- began in English 14c. Related: Comforted; comforting.