Online Etymology Dictionary

capital (adj.): early 13c., "of or pertaining to the head," from Old French capital, from Latin capitalis "of the head," hence "capital, chief, first," from caput (genitive capitis) "head" (see capitulum). Meaning "main, principal, chief, dominant, most important" is from early 15c. in English. Capital letter for an upper case one is attested from late 14c. The modern informal sense of "excellent, first-rate" is dated from 1762 in OED (as an exclamation of approval, OED's first example is 1875), perhaps from earlier use of the word in reference to ships, "first-rate, powerful enough to be in the line of battle," attested from 1650s, fallen into disuse after 1918.

A capital crime (1520s) is one that affects the life or "head;" capital had a sense of "deadly, mortal" from late 14c. in English, a sense also found in Latin. The felt connection between "head" and "life, mortality" also existed in Old English: as in heafodgilt "deadly sin, capital offense," heafdes þolian "to forfeit life." Capital punishment was in Blackstone (1765) and classical Latin capitis poena. Capital gain is recorded from 1921. Capital goods is recorded from 1899. Related: Capitally.
capital (n.1): early 15c., "a capital letter," from capital (adj.). The meaning "capital city" is first recorded 1660s (the Old English word was heafodstol). The financial sense is from 1610s (Middle English had chief money "principal fund," mid-14c.), from Medieval Latin capitale "stock, property," noun use of neuter of capitalis "capital, chief, first." (The noun use of this adjective in classical Latin was for "a capital crime.")
[The term capital] made its first appearance in medieval Latin as an adjective capitalis (from caput, head) modifying the word pars, to designate the principal sum of a money loan. The principal part of a loan was contrasted with the "usury"--later called interest--the payment made to the lender in addition to the return of the sum lent. This usage, unknown to classical Latin, had become common by the thirteenth century and possibly had begun as early as 1100 A.D., in the first chartered towns of Europe. [Frank A. Fetter, "Reformulation of the Concepts of Capital and Income in Economics and Accounting," 1937, in "Capital, Interest, & Rent," 1977]
Also see cattle, and compare sense development of fee, pecuniary.
capital (n.2): "head of a column or pillar," late 13c., from Anglo-French capitel, Old French chapitel, or directly from Latin capitellum "little head," diminutive of caput (see capitulum).
capital letter (n.): late 14c.; see capital (adj.). So called because it is at the "head" of a sentence or word.
capitalise (v.): chiefly British English spelling of capitalize (q.v.). For suffix, see -ize.
capitalism (n.): 1854, "condition of having capital;" from capital (n.1) + -ism. Meaning "political/economic system which encourages capitalists" is recorded from 1872.
capitalist (n.): 1791, "man of money," from French capitaliste, a coinage of the Revolution and a term of reproach; see capital (n.1) + -ist. Related: Capitalistic.
capitalization (n.): 1860, "act of converting (assets) to capital," noun of action from capitalize in the financial sense. Meaning "act of writing or printing in capital letters" is recorded from 1864.
capitalize (v.): "write or print in capital letters," 1764, from capital (n.1) + -ize. Meaning "to convert (assets) to capital" is recorded from 1868. Related: Capitalized; capitalizing.
capitate (adj.): "head-shaped," 1660s, from Latin capitatus "headed," from caput "head" (see capitulum).
capitation (n.): 1610s, "counting of heads," from Late Latin capitationem (nominative capitatio), noun of action from past participle stem of a verb derived from caput "head" (see capitulum). Meaning "levying of a poll tax" is from 1640s.
Capitol (n.): "building where U.S. Congress meets," 1793 (in writings of Thomas Jefferson), from Latin Capitolium, temple of Jupiter Optimus Maximus on the Capitoline Hill in ancient Rome. Used earlier of Virginia state houses (1699). Its use in American public architecture deliberately evokes Roman republican imagery. With reference to the Roman citadel, it is recorded in English from late 14c., via Old North French capitolie. Relationship of Capitoline to capital is likely but not certain.
capitulate (v.): 1570s, "to draw up in chapters" (i.e., under "heads"), in part a back-formation from capitulation, in part from Medieval Latin capitulatus, past participle of capitulare "to draw up in heads or chapters, arrange conditions." Often of terms of surrender, hence meaning "to yield on stipulated terms" (1680s). Related: Capitulated; capitulating.
capitulation (n.): 1530s, "an agreement," from Middle French capitulation, noun of action from capituler "agree on specified terms," from Medieval Latin capitulare "to draw up in heads or chapters, arrange conditions," from capitulum "chapter," in classical Latin "heading," literally "a little head," diminutive of caput (genitive capitis) "head" (see capitulum). Meaning narrowed by mid-17c. to "make terms of surrender."
capitulum (n.): used in various senses in English; Latin, literally "little head," diminutive of caput "head," also "leader, guide, chief person; summit; capital city; origin, source, spring," figuratively "life, physical life;" in writing "a division, paragraph;" of money, "the principal sum," from PIE *kaput- "head" (see head (n.)).
capnography (n.): also (and originally) kapnography, "drawing by means of smoke" (or carbon deposited by a flame), 1871, from Greek kapnos "smoke" + -graphy. See "Art-Journal," vol. x, 1871, p. 249. Related: Capnographic; kapnographic.
capnomancy (n.): "divination by smoke," c. 1600, from Latinized form of Greek kapnos "smoke" + -mancy.
capo (n.1): "leader of a Mafia 'family,' " 1952, Italian, literally "head" (see head (n.)).
capo (n.2): "pitch-altering device for a stringed instrument," 1946, short for capo tasto (1876), from Italian, literally "head stop" (see head (n.)).
capon (n.): "a castrated cock," late Old English capun, from Latin caponem (nominative capo) "castrated cock" (also source of French chapon, Spanish capon, Italian cappone), perhaps literally "to strike off," from PIE root *(s)kep- "to cut" (see hatchet (n.)). Probably reinforced in Middle English by cognate Old North French capon.
capote (n.): "long cloak with a hood," 1812, from French capote, fem. of capot (17c.), diminutive of cape (see cape (n.1)).
Cappadocia (n.): ancient name for the region roughly corresponding to modern Turkey, from Greek Kappadokía, perhaps ultimately from Persian Hvaspadakhim "land of fine horses." In ancient Athens, Cappadocians were notorious as knaves and cowards, but the region's horses were celebrated.
cappella: see a cappella.
cappuccino (n.): 1948, from Italian cappuccino, from Capuchin in reference to the beverage's color and its supposed resemblance to that of the brown hoods of the Friars Minor Capuchins (see Capuchin).
Capri: island in the Bay of Naples, of unknown origin: Latin capra "she-goat," Greek kapros "boar," Etruscan capra "burial place" all have been suggested. As a type of wine, 1877; as a type of pants, 1956 (see Capri pants).
Capri pants: 1956 (said to have been designed c. 1948), from Capri, Italian island; so called perhaps because they were first popular in Capri, which was emerging as a European holiday destination about this time (compare Bermuda shorts).
capriccio (n.): 1690s as a term in music for a kind of free composition, from Italian capriccio "sudden start or motion" (see caprice). Earlier it meant "prank, trick" (1660s); "caprice" (c. 1600).
caprice (n.): "sudden change of mind," 1660s, from French caprice "whim" (16c.), from Italian capriccio "whim," originally "a shivering," possibly from capro "goat," with reference to frisking, from Latin capreolus "wild goat" (see cab). But another theory connects the Italian word with capo "head" + riccio "curl, frizzled," literally "hedgehog" (from Latin ericius). The notion in this case would be of the hair standing on end in horror, hence the person shivering in fear.
capricious (adj.): 1590s, from French capricieux "whimsical" (16c.), from Italian capriccioso, from capriccio (see caprice). Related: Capriciously; capriciousness.
Capricorn: zodiac sign, late Old English, from Latin Capricornus, literally "horned like a goat," from caper (genitive capri) "goat" (see cab) + cornu "horn," from PIE *ker- (1) "horn; head, uppermost part of the body" (see horn (n.)); a loan-translation of Greek Aigokheros, the name of the constellation. Extended 1894 to persons born under the sign.
caprine (adj.): "goat-like," c. 1600, from Latin caprinus, from caper "goat" (see cab) + adjectival suffix -inus (see -ine (1)).
capris (n.): "Capri pants," 1966, see Capri pants.
capsaicin: from capsicum, from which it is extracted + chemical suffixes.
Capsicum (n.): genus of pepper plants, 1660s, of unknown origin, a word said to have been chosen by French botanist Joseph Pitton de Tournefort (1656-1708); perhaps irregularly formed from Latin capsa "box" (see case (n.2)).
capsid (adj.): 1889 in biology, "pertaining to capsidae," a type of insect, from Latin capsa "box" (see case (n.2)).
capsize (v.): 1780 (transitive); 1792 (intransitive), a nautical word of obscure origin, perhaps (as Skeat suggests) from Spanish capuzar "to sink by the head," from cabo "head," from Latin caput (see capitulum). For sense, compare French chavirer "to capsize, upset," faire capot "capsize;" Provençal cap virar "to turn the head." Related: Capsized; capsizing.
capstan (n.): late 14c., from Old French cabestant, from Old Provençal cabestan, from capestre "pulley cord," from Latin capistrum "halter," from capere "to hold, take" (see capable).
capstone (n.): also cap-stone, topmost stone in a construction, 1680s, from cap + stone (n.). Earliest use is figurative.
capsule (n.): 1650s, from French capsule "a membranous sac" (16c.), from Latin capsula "small box or chest," diminutive of capsa "box, case, chest" (see case (n.2)). Medicinal sense is 1875; shortened form cap is from 1942. Sense in space capsule is first recorded 1954. As an adjective from 1938. Related: Capsular.
capsulize (v.): of news, etc., 1950, from capsule + -ize. Related: Capsulized; capsulizing.
captain (n.): late 14c., capitayn, "a leader, chief, one who stands at the head of others," from Old French capitaine "captain, leader," from Late Latin capitaneus "chief," noun use of adjective capitaneus "prominent, chief," from Latin caput (genitive capitis) "head" (see capitulum).

Military sense of "officer who commands a company" (rank between major and lieutenant) is from 1560s; naval sense of "officer who commands a man-of-war" is from 1550s, extended to "master or commander of a vessel of any kind" by 1704. Sporting sense is first recorded 1823.
captain (v.): 1590s, from captain (n.). Related: Captained; captaining.
captaincy (n.): 1818, from captain (n.) on the model of lieutenancy or some similar word where the -c- is etymologically justified.
captation (n.): 1520s, from Middle French captation, from Latin captationem (nominative captatio) "a reaching after, a catching at," noun of action from past participle stem of captare (see catch (v.)).
caption (n.): late 14c., "taking, seizure," from Old French capcion "arrest, capture, imprisonment," or directly from Latin captionem (nominative capito) "a catching, seizing, holding, taking," noun of action from past participle stem of capere "to take" (see capable).

From 17c. used especially in law, and there via its appearance at the head of legal document involving seizure ("Certificate of caption", etc.), the word's sense was extended to "the beginning of any document;" thus "heading of a chapter or section of an article" (1789), and, especially in U.S., "description or title below an illustration" (1919).
caption (v.): by 1901, from caption (n.). Related: Captioned; captioning.
captious (adj.): c. 1400, capcyus, from Middle French captieux (15c.) or directly from Latin captiosus "fallacious," from captionem (nominative captio) "a deceiving, fallacious argument," literally "a taking (in)," from captus, past participle of capere "to take, catch" (see capable). Related: Captiously; captiousness.
captivate (v.): 1520s, "to enthrall with charm," from Late Latin captivatus, past participle of captivare "to take, capture," from captivus (see captive). Literal sense (1550s) is rare or obsolete in English, which uses capture (q.v.). Latin captare "to take, hold" also had a transferred sense of "to entice, entrap, allure." Related: Captivated; captivating; captivatingly.
captive (adj.): late 14c., "imprisoned, enslaved," from Latin captivus "caught, taken prisoner," from captus, past participle of capere "to take, hold, seize" (see capable). As a noun from c. 1400; an Old English noun was hæftling, from hæft "taken, seized."
captivity (n.): late 14c., Old French *captivite or directly from Latin captivitatem (nominative captivitas), from captivus (see captive (n.)). An Old English cognate word for it was gehæftnes (see haft).