Online Etymology Dictionary

kilometer (n.): 1810, from French kilomètre (1795); see kilo- + meter (n.2). Related: Kilometric.
kilometre (n.): chiefly British English spelling of kilometer; also see -re.
kilowatt (n.): 1884, from kilo- + watt. Kilowatt hour is from 1892. Related: Kilowattage.
Kilroy: U.S. military graffito character, 1945, said to be either Sgt. Francis J. Kilroy Jr., U.S. Army Air Transport, whose friend or friends began writing his name everywhere as a prank; or war materiéls inspector James J. Kilroy of Quincy, Mass., who wrote "Kilroy was here" on everything he checked.
kilt (n.): "plaited tartan skirt," c.1730, from Middle English verb kilten "to tuck up" (mid-14c.), from a Scandinavian source (cf. Danish kilte op "to tuck up;" Old Norse kilting "shirt," kjalta "fold made by gathering up to the knees").
kilt (v.): "to tuck up," mid-14c., of Scandinavian origin; cf. Danish kilte, Swedish kilta "to tuck up;" see kilt (n.). Related: Kilted; kilting.
kilter (n.): in out of kilter (1620s) variant of English dialectal kelter (c.1600) "good condition, order," of unknown origin.
Kimberley: South African city, founded 1871; also region in northwest Australia; both named for John Wodehouse, 1st Earl of Kimberley, who was British secretary of state for the colonies; the earldom is from a place in Norfolk, England (the name alsi is found in Nottinghamshire, Warwickshire). The second element is Old English leah "meadow, clearing in a woodland" (see lea), the first reflect various Old English personal names; the one in Norfolk appears first as Chineburlai (1086) and seems to be "clearing of a woman called Cyneburg."
Kimberly: fem. proper name, apparently from the place or surname Kimberley. Not much known in U.S. before 1946; a top-10 name for girls born there 1964-1977.
kimchi (n.): 1898, from Korean.
kimono (n.): 1630s, from Japanese kimono, literally "a thing put on," from ki "wear, put on" + mono "thing."
kin (n.): c.1200, from Old English cynn "family; race; kind, sort, rank; nature; gender, sex," from Proto-Germanic *kunjam "family" (cf. Old Frisian kenn, Old Saxon kunni, Old Norse kyn, Old High German chunni "kin, race;" Danish and Swedish kön, Middle Dutch, Dutch kunne "sex, gender;" Gothic kuni "family, race," Old Norse kundr "son," German Kind "child"), from PIE *gen(e)- "to produce" (see genus).
kinase (n.): 1902, from Greek kinein "to move" (see cite) + chemical suffix -ase.
kind (n.): "class, sort, variety," from Old English gecynd "kind, nature, race," related to cynn "family" (see kin), from Proto-Germanic *gakundjaz "family, race" (see kind (adj.)). Ælfric's rendition of "the Book of Genesis" into Old English came out gecyndboc. The prefix disappeared 1150-1250. No exact cognates beyond English, but it corresponds to adjective endings such as Goth -kunds, Old High German -kund. Also in English as a suffix (mankind, etc.). Other earlier, now obsolete, senses in English included "character, quality derived from birth" and "manner or way natural or proper to anyone." Use in phrase a kind of (1590s) led to colloquial extension as adverb (1804) in phrases such as kind of stupid ("a kind of stupid (person)").
kind (adj.): "friendly, deliberately doing good to others," from Old English gecynde "natural, native, innate," originally "with the feeling of relatives for each other," from Proto-Germanic *gakundiz "natural, native," from *kunjam (see kin), with collective prefix *ga- and abstract suffix *-iz. Sense development from "with natural feelings," to "well-disposed" (c.1300), "benign, compassionate" (c.1300).
kind-hearted (adj.): also kindhearted, 1530s; see kind (adj.) + hearted. Related: Kindheartedly, kindheartedness.
kinda: 1890, representing a casual pronunciation of kind of.
kindergarten (n.): 1852, from German, literally "children's garden," from Kinder "children" (plural of Kind "child") + Garten "garden" (see yard (n.1)). Coined 1840 by German educator Friedrich Fröbel (1782-1852) in reference to his method of developing intelligence in young children.
Kindergarten means a garden of children, and Froebel, the inventor of it, or rather, as he would prefer to express it, the discoverer of the method of Nature, meant to symbolize by the name the spirit and plan of treatment. How does the gardener treat his plants? He studies their individual natures, and puts them into such circumstances of soil and atmosphere as enable them to grow, flower, and bring forth fruit,-- also to renew their manifestation year after year. [Mann, Horace, and Elizabeth P. Peabody, "Moral Culture of Infancy and Kindergarten Guide," Boston, 1863]
The first one in England was established 1850 by Johannes Ronge, German Catholic priest; in America, 1868, by Elizabeth Peabody of Boston, Mass. Taken into English untranslated, whereas other nations that borrowed the institution nativized the name (cf. Danish börnehave, Modern Hebrew gan yeladim, literally "garden of children"). Sometimes partially anglicized as kindergarden (attested by 1879).
kindergartener (n.): "kindergarten teacher," 1872, from kindergarten + -er (1). The German form kindergartner is recorded in American English from 1863. As "kindergarten pupil," attested from 1935.
kindle (v.): c.1200, cundel, "to set fire to, to start on fire," probably from a Scandinavian source akin to Old Norse kynda "to kindle, to light a fire," Swedish quindla "kindle," of uncertain origin, + frequentative suffix -le. Figurative use from c.1300. Intransitive sense "to begin to burn, to catch fire" is from c.1400. Related: Kindled; kindling.

Influenced in form, and sometimes in Middle English in sense, with kindel "to give birth" (of animals), "bring forth, produce" (c.1200), from kindel (n.) "offspring of an animal, young one," from Old English gecynd (see kind (n.)) + -el.
kindling (n.): "material for lighting fire," 1510s, from present participle of kindle (v.). Earlier "a setting alight" (c.1300).
kindly (adj.): early 14c., from Old English gecyndelic "natural, innate; suitable, lawful;" see kind (adj.) + -ly (1). Related: Kindliness. The adverb meaning "with kind feelings" is from Old English gecyndelice, with -ly (2).
kindness (n.): c.1300, "courtesy, noble deeds," from kind (adj.) + -ness. Meaning "kind deeds; kind feelings" is from late 14c. Old English kyndnes meant "nation; produce, an increase."
kindred (n.): c.1200, kinraden, compound of kin (q.v.) + -rede, from Old English ræden "condition, rule," related to rædan "to advise, rule" (see read). With intrusive -d- (17c.) probably for phonetic reasons (cf. thunder) but perhaps encouraged by kind (n.). As an adjective, 1520s, from the noun.
kine (n.): archaic plural of cow, a double plural (cf. children) or genitive plural of Middle English kye "cows," from Old English cy (genitive cyna), plural of cu "cow."
kinema: see cinema.
kinematics (n.): "science of motion," 1840, from French cinématique (Ampère, 1834), from Greek kinesis "movement, motion" (see cite). Related: Kinematic (1864); kinematical.
kinesics (n.): study of body language, 1952, from Greek kinesis "movement, motion" (see cite) + -ics. Related: kinesic.
kinesiology (n.): 1894, from kinesi-, comb. form of Greek kinesis "movement, motion" (see cite) + -ology. Related: Kinesiological; kinesiologically.
kinesis (n.): "physical movement," 1819, from Greek kinesis "movement, motion" (see cite).
kinesthesia (n.): also kinaesthesia, 1888, Modern Latin compound of Greek kinein "to set in motion; to move" (see cite) + aisthesis "perception" (see anaesthesia).
kinesthetic (adj.): also kinaesthetic, "pertaining to kinesthesia," 1880, coined by British neurologist Henry Charlton Bastian (1837-1915) from Greek kinein "to move" (see cite) + aisthesis "sensation" (see anaesthesia). Perhaps on model of aesthetic, prosthetic.
kinesthetics (n.): also kinaesthetics, by 1893, from kinesthetic "pertaining to kinesthesia" + -ics.
kinetic (adj.): "relating to motion," 1841, from Greek kinetikos "moving, putting in motion," from kinetos "moved," verbal adjective of kinein "to move" (see cite).
Buster Keaton's subject was kinetic man, a being he approached with the almost metaphysical awe we reserve for a Doppelgänger. This being was, eerily, himself, played by himself, then later in a projection room, watched by himself: an experience never possible to any generation of actors in the previous history of the world. [Hugh Kenner, "The Counterfeiters," 1968]
Related: Kinetical; kinetically.
kinetics (n.): 1864, from kinetic; see -ics.
kineto-: word-forming element meaning "motion," from Greek kineto-, comb. form of kinetos (see kinetic).
kinfolk (n.): also kin-folk, 1802, principally American English, but the earliest references are British, from kin (n.) + folk (n.). Kinsfolk is recorded from 1844.
king (n.): Old English cyning "king, ruler," from Proto-Germanic *kuninggaz (cf. Dutch koning, Old Norse konungr, Danish konge, Old Saxon and Old High German kuning, Middle High German künic, German König). Possibly related to Old English cynn "family, race" (see kin), making a king originally a "leader of the people;" or from a related root suggesting "noble birth," making a king originally "one who descended from noble birth." The sociological and ideological implications render this a topic of much debate.

Finnish kuningas "king," Old Church Slavonic kunegu "prince" (Russian knyaz, Bohemian knez), Lithuanian kunigas "clergyman" are loans from Germanic.
As leon is the king of bestes. [John Gower, "Confessio Amantis," 1390]
In Old English, used for names of chiefs of Anglian and Saxon tribes or clans, then of the states they founded. Also extended to British and Danish chiefs they fought. The chess piece so called from early 15c.; the playing card from 1560s; use in checkers/draughts first recorded 1820. Applied in nature to species deemed remarkably big or dominant (e.g. king crab, 1690s). In marketing, king-size is from 1939, originally of cigarettes.
[I]t was [Eugene] Field who haunted the declining years of Creston Clarke with his review of that actor's Lear. ... Said he, "Mr. Clarke played the King all the evening as though under constant fear that someone else was about to play the Ace." ["Theatre Magazine," January 1922]
King Kong: U.S. film released 1933.
king's evil (n.): "scrofula," late 14c., translates Medieval Latin regius morbus; so called because the kings of England and France claimed to heal it by their touch. In England, the custom dates from Edward the Confessor and was continued through the Stuarts (Charles II touched 90,798 sufferers) but was ended by the Hanoverians (1714).
kingdom (n.): Old English cyningdom; see king + -dom. Cognate with Old Saxon kuningdom, Middle Dutch koninghdom, Old Norse konungdomr. The usual Old English word was cynedom; Middle English also had kingrick (for second element, see Reichstag). Meaning "one of the realms of nature" is from 1690s. Kingdom-come "the next world" (1785) is from the Lord's Prayer.
kingfisher (n.): mid-15c., originally king's fisher, for obscure reasons; see king + fisher.
kingmaker (n.): also king-maker, 1590s, originally in reference to the 15c. Earl of Warwick.
kingpin (n.): also king-pin, 1801 as the name of the large pin in the game of kayles (similar to bowls except a club or stick was thrown instead of a ball; cf. "Games, Gaming and Gamesters' Laws," Frederick Brandt, London, 1871), from king with a sense of "chief" + pin (n.). The modern use is mainly figurative and is perhaps from the word's use as another name for the king-bolt (itself from 1825) in a machinery, though the figurative use is attested earlier (1867) than the literal.
Kings: biblical book, late 14c., so called because it tells the history of the kings of Judah and Israel.
kingship (n.): early 14c., from king + -ship.
kink (n.): 1670s, a nautical term, from Dutch kink "twist in a rope" (also found in French and Swedish), probably related to Old Norse kikna "to bend backwards, sink at the knee" (see kick). Figurative sense of "odd notion, mental twist" first recorded in American English, 1803, in writings of Thomas Jefferson. As a verb, 1690s, from the noun.
kinkajou (n.): 1796, from French (1670s), from an Algonquian word.
kinky (adj.): 1844, "full of kinks, twisted, curly," from kink + -y (2). Meaning "odd, eccentric, crotchety" is from 1859; that of "sexually perverted" is from 1959. Related: Kinkiness.
kino-: before vowels, kin-, word-forming element meaning "motion," from Greek kino-, from kinein "to move" (see cite).