Online Etymology Dictionary

calling (n.): "vocation," mid-13c., verbal noun from call (v.). The sense traces to I Cor. vii:20.
calliope (n.): 1858, "steam-whistle keyboard organ," named for Calliope, ninth and chief muse, presiding over eloquence and epic poetry, Latinized from Greek Kalliope, literally "beautiful-voiced," from kalli-, combining form of kallos "beauty" (see Callisto) + opos (genitive of *ops) "voice," related to Latin vox (see voice (n.)).
calliper (n.): variant of caliper. Related: Callipers.
callipygian (adj.): "of, pertaining to, or having beautiful buttocks," 1800, Latinized from Greek kallipygos, name of a statue of Aphrodite at Syracuse, from kalli-, combining form of kallos "beauty" (see Callisto) + pyge "rump, buttocks." Sir Thomas Browne (1646) refers to "Callipygæ and women largely composed behinde."
Callisto: fourth moon of Jupiter; in classical mythology a nymph, mother of Arcas by Zeus, turned to a bear by Hera, from Greek kallistos, superlative of kalos "beautiful, beauteous," from PIE *kal-wo-, suffixed form of root *kal- (2) "beautiful." Feminized as proper name Callista.
callithumpian (adj.): 1836, U.S. colloquial, probably a fanciful construction. The "English Dialect Dictionary" reports Gallithumpians as a Dorset and Devon word from 1790s for a society of radical social reformers, and also in reference to "noisy disturbers of elections and meetings" (1770s). The U.S. reference is most commonly "a band of discordant instruments" or bangers on pots and pans, especially to "serenade" a newlywed couple to show disapproval of one or the other or the match.
callosal (adj.): "pertaining to the corpus callosum," from Latin callosus (see callous) + -al (1).
callous (adj.): c. 1400, "hardened," in the physical sense, from Latin callosus "thick-skinned," from callus, callum "hard skin" (see callus). The figurative sense of "unfeeling" appeared in English by 1670s. Related: Callously; callousness.
callow (adj.): Old English calu "bare, bald," from Proto-Germanic *kalwa- (source also of Middle Dutch calu, Dutch kaal, Old High German kalo, German Kahl), from PIE root *gal- (1) "bald, naked" (source also of Russian golyi "smooth, bald"). From young birds with no feathers, meaning extended to any young inexperienced thing or creature (1570s). Apparently not related to Latin calvus "bald."
callus (n.): "hardened skin," 1560s, from Latin callus, variant of callum "hard skin," related to callere "be hard," from PIE root *kal- (3) "hard" (source also of Sanskrit kalika "bud," Old Irish calath "hard," Old Church Slavonic kaliti "to cool, harden").
calm (adj.): late 14c., from Old French calme "tranquility, quiet," traditionally from Old Italian calma, from Late Latin cauma "heat of the mid-day sun" (in Italy, a time when everything rests and is still), from Greek kauma "heat" (especially of the sun), from kaiein "to burn" (see caustic). Spelling influenced by Latin calere "to be hot." Figurative application to social or mental conditions is 16c.
calm (n.): late 14c., from Old French calme, carme "stillness, quiet, tranquility," from the adjective (see calm (adj.)).
calm (v.): late 14c., from Old French calmer or from calm (adj.). Related: Calmed; calming.
calmative (adj.): by 1831, from French calmatif; see calm (adj.) + -ative. A hybrid word; purists prefer sedative. "The Latinic suffix is here defensible on the ground of It. and Sp. calmar, F. calmer ...." [OED].
calmly (adv.): 1590s, from calm (adj.) + -ly (2).
calmness (n.): 1510s, from calm (adj.) + -ness.
calomel (n.): old name for mercurous chloride, 1670s, from French calomel, supposedly (Littré) from Greek kalos "beautiful" (see Callisto) + melas "black;" but as the powder is yellowish-white this seems difficult. "It is perhaps of significance that the salt is blackened by ammonia and alkalis" [Flood].
Calor (n.): proprietary name for a type of liquid gas sold in Britain, 1936, from Latin calor, literally "heat" (see calorie).
caloric (n.): hypothetical fluid in a now-discarded model of heat exchange, 1792, from French calorique, coined in this sense by Lavoisier, from Latin calorem "heat" (nominative calor; see calorie). The adjective is recorded from 1865.
calorie (n.): 1866, from French calorie, from Latin calor (genitive caloris) "heat," from PIE *kle-os-, suffixed form of root *kele- (1) "warm" (source also of Latin calidus "warm," calere "be hot;" Sanskrit carad- "harvest," literally "hot time;" Lithuanian silti "become warm," silus "August;" Old Norse hlær, Old English hleow "warm").

In scientific use, largely replaced 1950 by the joule. As a unit of energy, defined as "heat required to raise 1 gram of water 1 degree Celsius" (the small or gram calorie), but also as "heat required to raise 1 kilogram of water 1 degree Celsius" (the large calorie or kilocalorie).
calorimeter (n.): 1794, from calorie + -meter. A hybrid word.
calque (n.): "loan translation of a foreign word or phrase," from French calque, literally "a copy," from calquer "to trace by rubbing" (itself borrowed in English 1660s as calk), introduced 16c. from Italian calcare, from Latin calcare "to tread, to press down."
calumet (n.): 1660s, from Canadian French calumet, from Norman French calumet "pipe" (Old French chalemel, 12c., Modern French chalumeau), from Latin calamellus, diminutive of calamus "reed; something made of reed or shaped like a reed" (see shawm).
calumniate (v.): 1550s, from Latin calumniatus, past participle of calumniari "to accuse falsely," from calumnia "slander, false accusation" (see calumny). Related: Calumniated; calumniating.
calumniation (n.): 1540s, noun of action from calumniate (v.).
calumniator (n.): 1690s, from Latin calumniator, agent noun from calumniari (see calumniate (v.)).
calumnious (adj.): late 15c., from Latin calumniosus, from calumnia (see calumny). Related: Calumniously.
calumny (n.): "False & malicious misrepresentation of the words or actions of others, calculated to injure their reputation" [Fowler], mid-15c., from Middle French calomnie (15c.), from Latin calumnia "trickery, subterfuge, misrepresentation, malicious charge," from calvi "to trick, deceive," from PIE root *kel- (6) "to deceive, confuse" (source also of Greek kelein "to bewitch, seduce, beguile," Gothic holon "to deceive," Old Norse hol "praise, flattery," Old English hol "slander," holian "to slander").
Calvary: name of the mount of the Crucifixion, late 14c., from Latin Calvaria (Greek Kraniou topos), translating Aramaic gulgulta "place of the skull" (see Golgotha). Rendered literally in Old English as Heafodpannan stow. Latin Calvaria is related to calvus "bald" (see Calvin).
calve (v.): Old English cealfian, from cealf "calf" (see calf (n.1)). Of icebergs, 1837. Related: Calved; calving.
Calvin: John Calvin (1509-1564), Protestant leader, born Jean Caulvin, the surname related to French Chauvin (compare chauvinism), from Latin calvus "bald," from PIE *kle-wo- "bald."
Calvinism (n.): 1560s, from John Calvin (1509-1564), Protestant reformer, + -ism. Alternative form Calvinian was in use in 1566. Generalized association with stern moral codes and predestination is attested since at least 1853. Related: Calvinist.
Calypso: sea nymph in the "Odyssey," literally "hidden, hider" (perhaps originally a death goddess) from Greek kalyptein "to cover, conceal," from PIE *kel- "to cover, conceal, save," root of English Hell (see cell). The type of West Indian song is so called from 1934, but the origin of the name is obscure.
calyx (n.): 1680s, from Latin calyx, from Greek kalyx "seed pod, husk, outer covering" (of a fruit, flower bud, etc.), from root of kalyptein "to cover, conceal" (see cell). The proper plural is calyces. Some sources connect the word rather with Greek kylix "drinking cup."
cam (n.1): "a projecting part of a rotating machinery," 1777, from Dutch cam "cog of a wheel," originally "comb;" cognate of English comb (n.). This might have combined with English camber "having a slight arch;" or the whole thing could be from camber.
cam (n.2): abbreviation of camera, by 1990.
camaraderie (n.): 1840, from French camaraderie, from camarade "comrade" (see comrade).
camber (n.): 1610s, nautical term, from Old French cambre, chambre "bent," from Latin camurum (nominative camur) "crooked, arched;" related to camera.
cambium (n.): 1670s in botany sense, from Late Latin cambium "exchange," from Latin cambiare "change" (see change (v.)).
Cambodia: from Kambu, legendary ancestor of the people. Related: Cambodian.
Cambrian (adj.): 1650s, "from or of Wales or the Welsh," from Cambria, variant of Cumbria, Latinized derivation of Cymry, the name of the Welsh for themselves, from Old Celtic Combroges "compatriots." Geological sense (of rocks first studied in Wales and Cumberland) is from 1836.
cambric (n.): late 14c., from Kamerijk, Flemish form of Cambrai, city in northern France where the cloth was originally made, from Latin Camaracum. The modern form of the English word has elements from both versions of the name.
Cambridge: Old English Grontabricc (c.745) "Bridge on the River Granta" (a Celtic river name, of obscure origin). The change to Cante- and later Cam- was due to Norman influence. The river name Cam is a back-formation in this case, but Cam also was a legitimate Celtic river name, meaning "crooked."
camcorder (n.): 1982, from camera and recorder.
came: past tense of come.
camel (n.): Old English camel, perhaps via Old North French camel (Old French chamel, Modern French chameau), from Latin camelus, from Greek kamelos, from Hebrew or Phoenician gamal, perhaps related to Arabic jamala "to bear."

Another Old English word for the beast was olfend, apparently based on confusion of camels with elephants in a place and time when both were known only from travelers' vague descriptions. The Arabian have one hump (the lighter variety is the dromedary); the Bactrian have two.
cameleon (n.): obsolete form of chameleon.
camellia (n.): 1753, named by Linnæus from Latinized form of Georg Joseph Kamel (1661-1706), Moravian-born Jesuit who described the flora of the island of Luzon, + abstract noun ending -ia.
Camelot (n.): a name first found in medieval French romances; it corresponds to Latin Camuladonum, the Roman forerunner of Colchester, which was an impressive ruin in the Middle Ages. But Malory identifies it with Winchester and Elizabethans tended to see it as Cadbury Castle, an Iron Age hill fort near Glastonbury.
Camembert (n.): type of soft, rich cheese, 1878, from name of village near Argentan, Normandy, where it originally was made. The place name is Medieval Latin Campus Maimberti "field of Maimbert" (a West Germanic personal name).