Online Etymology Dictionary

Kidderminster: type of two-ply carpet, 1832, named for the town in England where it was manufactured. The place name is Anglo-French Chideminstre, literally "Cydder's Monastery," from an Old English personal name.
kiddo (n.): 1893, familiar form of kid (n.) in the "child" sense.
kiddy (n.): also kiddie; 1570s as "young goat;" 1780 as "flash thief;" 1889 as "little child," from various senses of kid (n.) + -y (3). Other diminutives in the "small child" sense were kidlet (1889), kidling (1899). Related: Kiddies.
kidnap (v.): 1680s, thieves' cant, a compound of kid (n.) "child" and nap (v.) "snatch away," which probably is a variant of nab (v.). Perhaps a back-formation from kidnapper, which is recorded earlier. Originally "to steal children to provide servants and laborers in the American colonies." Related: Kidnapped; kidnapping.
kidnapper (n.): 1670s; see kidnap (though this word is attested a few years earlier).
kidnapping (n.): 1680s, verbal noun from kidnap (v.).
kidney (n.): early 14c., kidenere, a word of unknown origin, perhaps a compound of Old English cwið "womb" (see bowel) + ey "egg" (see egg (n.)) in reference to the shape of the organ. Figurative sense of "temperament" is from 1550s. Kidney-bean is from 1540s, so called for its shape.
kielbasa (n.): 1951, from Polish kiełbasa "sausage" (cognate with Russian kolbasa, Serbo-Croatian kobasica); perhaps from Turkish kulbasti, "grilled cutlet," literally "pressed on the ashes." Or perhaps, via Jewish butchers, from Hebrew kolbasar "all kinds of meat."
Kiev: Ukrainian Kyyiv, of unknown origin; explanation from the name of a founding prince named Kiy probably is folk etymology. Related: Kievan.
kike (n.): derogatory slang for "a Jew," by 1901, American English; early evidence supports the belief that it was used at first among German-American Jews in reference to newcomers from Eastern Europe, perhaps because the names of the latter ended in -ki or -ky.
There is no charity organization of any kind here [a small city in Pennsylvania] and, what is sadder to relate, the Jews in this city will not form one; that is, if the present temper of the people can be used as a criterion. The German Jews are bitterly opposed to the "Kikes," as they persist in calling the Russian Jews .... ["Report of the National Conference of Jewish Charities in the United States," Cleveland, 1912]
Philip Cowen, first editor of "The American Hebrew," suggests a source in Yiddish kikel "circle." According to him, Jewish immigrants, ignorant of writing with the Latin alphabet, signed their entry forms with a circle, eschewing the customary "X" as a sign of Christianity. On this theory, Ellis Island immigration inspectors began calling such people kikels, and the term shortened as it passed into general use.
Kikuyu (n.): Bantu language of Kenya, 1904.
kil-: first element in many Celtic place names, meaning "cell (of a hermit); church; burial place," from Gaelic and Irish -cil, from cill, gradational variant of ceall "cell, church, burial place," from Latin cella (see cell).
Kilimanjaro: mountain in Africa, from Swahili, literally "mountain of the god of cold," from kilima "mountain" + njaro "god of cold."
Kilkenny: county in Leinster, Ireland. The county is named for its town, from Irish Cill Chainnigh "Church of (St.) Kenneth" (see kil-). The story of the Kilkenny cats, a pair of which fought until only their tails were left, is attested from 1807.
kill (v.): c. 1200, "to strike, hit, beat, knock;" c. 1300, "to deprive of life, put to death;" perhaps from an unrecorded variant of Old English cwellan "to kill, murder, execute" (see quell), but the earliest surviving recorded sense suggests otherwise. Related: Killed; killing.

Meaning "nullify or neutralize the qualities of" is from 1610s. Of time, 1728; of engines 1886; of lights, 1934. Kill-devil, colloquial for "rum," especially if new or of bad quality, is from 1630s. Dressed to kill first attested 1818 in a letter of Keats (compare killing (adj.) in the sense "overpowering, fascinating, attractive").
kill (n.2): "stream, creek," 1630s, American English, from Dutch kil "a channel," from Middle Dutch kille "riverbed, inlet." The word is preserved in place names in the Mid-Atlantic American states (such as Schuylkill, Catskill, Fresh Kills, etc.). A common Germanic word, the Old Norse form, kill, meant "bay, gulf" and gave its name to Kiel Fjord on the Baltic coast and thence to Kiel, the German port city founded there in 1240.
kill (n.1): early 13c., "a stroke, a blow," from kill (v.). Meaning "the act of killing" is from 1814 in hunting slang; that of "a killed animal" is from 1878. Lawn tennis serve sense is from 1903. The kill "the knockout" is boxing jargon, 1950. Kill ratio is from 1968, American English.
killable (adj.): 1755, from kill (v.) + -able.
killdeer (n.): also killdee, species of large North American ring-plover, 1731, American English. The name is imitative of its shrill, two-syllable cry.
killer (n.): late 15c., agent noun from kill (v.). But a surname, Ric[hard] Le Kyller is attested from 1288. Figurative use from 1550s. Meaning "impressive person or thing" is by 1900 (as an adjective, 1979); reduplicated form killer-diller attested by 1938. Killer whale is from 1854 (earlier simply killer 1725); killer instinct is attested from 1931, originally in boxing.
killing (adj.): mid-15c., "deadly, depriving of life," present participle adjective from kill (v.). Meaning "overpowering, fascinating, attractive" is 1630s, from the verb in a figurative sense "overwhelm (someone) by strong effect on the mind or senses." Meaning "very powerful in effect, exceedingly severe, so as to (almost) kill one" is from 1844. Related: Killingly.
killing (n.): "act of slaying, "mid-15c., verbal noun from kill (v.). Meaning "large profit" is from 1886, American English slang.
killjoy (n.): also kill-joy, 1776, from kill (v.) + joy. Kill formerly was used with other stems (for example kill-courtesy "boorish person," kill-cow "bully, big man," etc.; also compare Kellogg).
kiln (n.): Old English cyln, cylen "kiln, oven, furnace for drying or baking," from Latin culina "kitchen, cooking stove," unexplained variant of coquere "to cook" (see cook (n.)). According to OED, Old Norse kylna, Welsh cilin probably are from English.
kilo (n.): 1870, shortening of kilogram. Slang shortening key (in drug trafficking) is attested from 1968.
kilo-: word-forming element meaning "one thousand," introduced in French 1795, when the metric system was officially adopted there; irregularly reduced from Greek khilioi "thousand," from PIE *gheslo- "thousand," source also of Sanskrit sahasra-, Avestan hazanjra "thousand." "It is usually assumed that Lat. mille should be connected too" [Beekes]; see milli-. "In the metric system, kilo- means multiplied, & milli- divided, by 1000" [Fowler].
kilobyte (n.): 1970, from kilo- + byte.
kilocalorie (n.): also kilo-calorie, 1894, from kilo- + calorie.
kilocycle (n.): also kilo-cycle, 1921, from kilo- + cycle (n.).
kilogram (n.): "one thousand grams," standard of mass in the metric system, 1797, from French kilogramme (1795); see kilo- + gram.
kilojoule (n.): 1893, from kilo- + joule.
kiloliter (n.): 1810, from French kilolitre; see kilo- + liter.
kilolitre (n.): chiefly British English spelling of kiloliter; also see -re.
kilometer (n.): "one thousand meters," 1810, from French kilomètre (1795); see kilo- + meter (n.2). Related: Kilometric.
kilometre (n.): chiefly British English spelling of kilometer; also see -re.
kiloton (n.): also kilo-ton, 1950, from kilo- + ton (n.1).
kilowatt (n.): 1884, from kilo- + watt. Kilowatt hour is from 1892. Related: Kilowattage.
kilowatt (n.): also kilo-watt, 1884, from kilo- + watt.
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," originally the part of the belted plaid which hung below the waist, c. 1730, quelt, from Middle English verb kilten "to tuck up" (mid-14c.), from a Scandinavian source (compare 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., surviving in Scottish, a word of Scandinavian origin (compare Danish kilte "to truss, to tuck up," Swedish kilta "swaddle"); see kilt (n.). Related: Kilted; kilting.
kilter (n.): "order, good condition," in out of kilter (1620s), apparently a variant of English dialectal kelter (c. 1600) "good condition, order," a word 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 also 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" (also "gender, sex," a sense obsolete since Middle English), from Proto-Germanic *kunjam "family" (source also of Old Frisian kenn, Old Saxon kunni "kin, kind, race, tribe," Old Norse kyn, Old High German chunni "kin, race;" Danish kjön, Swedish kön, Middle Dutch, Dutch kunne "sex, gender;" Gothic kuni "family, race," Old Norse kundr "son," German Kind "child"), from PIE *gene- "to produce" (see genus).
In the Teutonic word, as in Latin genus and Greek [genos], three main senses appear, (1) race or stock, (2) class or kind, (3) gender or sex .... [OED]
Related to both words kind and to child. From 1590s as an adjective, from the noun and as a shortening of akin. Legal next of kin (1540s) does not include the widow, "she being specifically provided for by the law as widow" [Century Dictionary], and must be a blood relation of the deceased.
kinase (n.): 1902, from Greek kinein "to move" (see cite) + chemical suffix -ase.
kind (adj.): "friendly, deliberately doing good to others," Middle English kinde, from Old English (ge)cynde "natural, native, innate," originally "with the feeling of relatives for each other," from Proto-Germanic *kundi- "natural, native," from *kunjam "family" (see kin), with collective or generalizing prefix *ga- and abstract suffix *-iz. The word rarely appeared in Old English without the prefix, but Old English also had it as a word-forming element -cund "born of, of a particular nature" (see kind (n.)). Sense development probably is from "with natural feelings," to "well-disposed" (c. 1300), "benign, compassionate, loving, full of tenderness" (c. 1300).
kind (n.): "class, sort, variety," from Old English gecynd "kind, nature, race," related to cynn "family" (see kin), from Proto-Germanic *kundjaz "family, race," from PIE *gene- "to give birth, beget" (see genus).

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., also compare godcund "divine"). Other earlier, now obsolete, senses included "character, quality derived from birth" and "manner or way natural or proper to anyone."

Phrase a kind of (1590s) indicating something like or similar to something else led to the colloquial extension as adverb (1804) in phrases such as kind of stupid "a kind of stupid (person), (one) not far from stupidity." However "good usage" once condemned as inaccurate the use as an adjective as in our kind of people, some kind of joke.