Online Etymology Dictionary

Z: not a native letter in O.E.; in Anglo-Fr. words it represents the "ts" sound (cf. Anglo-Fr. fiz, from L. filius, modern Fitz); late 13c. it began to be used for the voiced "s" sound and had fully taken that role by 1400. For letter name, see zed.
"Thou whoreson Zed, thou vnnecessary Letter." ["King Lear," II.ii.69]
Series of zs to represent a buzzing sound first attested 1852; zees "spell of sleep, a nap" is slang first recorded 1963, Amer.Eng. student slang.
Zacchaeus: masc. proper name, from L.L. Zacchaeus, from Gk. Zakkhaios, from Heb. zakkay, lit. "pure, innocent," from zakhah "was clean, was pure."
Zachariah: masc. proper name, L.L. Zacharias, from Gk. Zakharias, from Heb. Zekharyahu, lit. "the Lord has remembered," from zakhar "he remembered."
zaftig: "alluringly plump, curvaceous, buxom," 1937, from Yiddish zaftik, lit. "juicy," from zaft "juice," from M.H.G. saft "juice" (see sap (n.1)).
zag (v.): 1793, from zig-zag (q.v.).
Zamboni: proprietary name for a machine used to resurface ice skating rinks, 1965, trademark of Frank J. Zamboni & Co., Paramount, Calif., claiming use since July 1962.
zany (n.): comic performer, 1588, from Fr. zani, from It. zani, zanni "a zany, clown," originally Zanni, Venetian dial. variant of Gianni, pet form of Giovanni "John." A stock character in old comedies, he aped the principal actors. The adj. is attested by 1869, from the noun.
zap: 1929 (sound effect), 1942 (v.), comic strip word (especially from "Buck Rogers in the Twenty-Fifth Century"), of imitative origin. Meaning "to erase electronically" is 1982.
Zarathustra: from Avestan Zarathushtra (see Zoroastrian).
zeal: 1382, from L.L. zelus "zeal, emulation" (cf. O.Fr. zel, It. zelo, Sp. celo), a Church word, from Gk. zelos "zeal, ardor, jealousy," which is of uncertain origin. Zealous first recorded 1535.
zealot: c.1300, "member of a militant 1st century Jewish sect which fiercely resisted the Romans in Palestine," from L.L. Zelotes, from Gk. zelotes "one who is a zealous follower," from zeloun "to be zealous," from zelos "zeal" (see zeal). Extended sense of "a fanatical enthusiast" first recorded 1638.
zebra: 1600, from It. zebra, perhaps from Port., earlier applied to a now-extinct wild ass, said to be Congolese [OED], or Amharic [Klein], but perhaps ult. from L. equiferus "wild horse," from equus "horse" + ferus (see fierce).
zebu: Asiatic ox, 1774, from Fr. zebu, ult. of Tibetan origin. First shown in Europe at the Paris fair of 1752.
Zebulon: masc. proper name, Biblical son of Jacob by Leah, from Heb. Zebhulun, from zebhul "a dwelling" + dim. suffix -on (cf. Gen. xxx:20).
Zechariah: masc. proper name, Biblical 11th of the Twelve Prophets; see Zachariah.
zed: c.1400, from M.Fr. zede, from L.L. zeta, from Gk. zeta, from Heb. zayin, letter name, lit. "weapon;" so called in allusion to the shape of this letter in ancient Hebrew. U.S. pronunciation zee is first attested 1677. Other dialectal names for the letter are izzard, ezod, uzzard and zod.
Zeiss: in ref. to spy-glasses or binoculars, 1905, from the firm founded by Ger. optical instrument manufacturer Carl Zeiss (1816-88).
zeitgeist: 1848, from Ger. Zeitgeist, lit. "spirit of the age," from Zeit "time" (see tide) + Geist "spirit" (see ghost).
Zen: school of Mahayana Buddhism, 1727, from Japanese, from Chinese ch'an, ult. from Skt. dhyana "thought, meditation," from PIE base *dhya "to see, contemplate."
Zend: 1715, "Parsee sacred book" (in full, Zend-Avesta, 1630), from O.Pers. zend, from Pahlavi zand "commentary." First used in ref. to the language of the Zend-Avesta in 1771 by Anquetiel-Duperron (1731-1805).
zenith: 1387, from O.Fr. cenith (Fr. zénith), from M.L. cenit, senit, bungled scribal transliteration of Arabic samt "road, path," abbreviation of samt ar-ras, lit. "the way over the head." Letter -m- misread as -ni-. The M.L. word may as well be influenced by the rough agreement of the Arabic term with classical L. semita "sidetrack, side path" (notion of "thing going off to the side"), from se- "apart" + *mi-ta-, suffixed zero-grade form of PIE base *mei- "to change" (see mutable).
Zenobia: fem. proper name, from Gk. Zenobia, lit. "the force of Zeus," from Zen, collateral form of Zeus, + bia "strength, force," cognate with Skt. jya "force, power" (see Jain).
Zenonian: 1843, pertaining to one of two Gk. thinkers: Zeno of Elea ("Zeno of the Paradoxes," 5c. B.C.E.), who disproved the possibility of motion; and Zeno of Citium (c. 300 B.C.E.), founder of stoicism.
zephyr: 1369, from O.E. Zefferus, from L. Zephyrus, from Gk. Zephyros "the west wind" (sometimes personified as a god), probably related to zophos "the west, the dark region, darkness, gloom." Sense of "mild breeze" is c.1610.
zeppelin: 1900, from Ger. Zeppelin, short for Zeppelinschiff "Zeppelin ship," after Count Ferdinand von Zeppelin (1838-1917), Ger. general who perfected its design.
zero: 1604, from It. zero, from M.L. zephirum, from Arabic sifr "cipher," translation of Skt. sunya-m "empty place, desert, naught" (see cipher). A brief history of the invention of "zero" can be found here. Meaning "worthless person" is recorded from 1813. The verb zero in is 1944, from the noun, on the notion of instrument adjustments. Zero tolerance first recorded 1972, originally U.S. political language.
zest: 1674, from Fr. zeste "piece of orange or lemon peel used as a flavoring," of unknown origin. Sense of "thing that adds flavor" is 1709; that of "keen enjoyment" first attested 1791.
zeta: Gk. letter, see zed.
zetetic: "proceeding by inquiry," 1645, from Mod.L. zeteticus, from Gk. zetetikos "searching, inquiring," from zetetos, verbal adj. of zetein "seek for, inquire into."
zeugma: 1580s, "a single word (usually a verb or adj.) made to refer to two or more words in a sentence," from Gk., lit. "a yoking," from zeugnynai "to yoke" (see jugular).
Zeus: supreme god of the ancient Greeks, 1706, from Gk., from PIE *dewos- "god" (cf. L. deus "god," O. Pers. daiva- "demon, evil god," O.C.S. deivai, Skt. deva-), from base *dyeu- "to gleam, to shine;" also the root of words for "sky" and "day" (see diurnal). The god-sense is originally "shining," but "whether as originally sun-god or as lightener" is not now clear.
Ziegfeld: in ref. to showgirls or stage revues, 1913, from Florenz Ziegfeld (1869-1932), U.S. theatrical producer, who staged annual "follies" from 1907-1931.
zig-zag: 1712, from Fr. zigzag (1680), perhaps from Ger. Zickzack (though this only is attested from 1703), possibly a reduplication of Zacke "tooth, prong." Earliest use in Ger. is in ref. to military siege approaches. Originally in Eng. used to describe the layout of certain garden paths. The verb is recorded from 1787.
ziggurat: 1877, from Assyrian ziqquratu "height, pinnacle," from zaqaru "to be high."
zilch: "nothing," 1966, from earlier sense of "meaningless speech" (1960), originally Mr. Zilch, (1931) comic character in the magazine "Ballyhoo." Perhaps from U.S. college slang (early 1900s) Joe Zilsch "an insignificant person." Probably a nonsense syllable, but Zilch is an actual Ger. surname of Slavic origin.
zillion: 1944, arbitrary coinage with no definite numerical value; first recorded in Damon Runyon.
zinc: 1651, from Ger. Zink, perhaps related to Zinke "prong, point;" said to have been used first by Paracelsus (c.1526) on analogy of the form of its crystals after smelting. Zinke is from O.H.G. zint "a point, jag," from P.Gmc. *tindja "tine" (cf. O.N. tindr "point, top, summit," O.E. tind "prong, spike;" cf. tine).
zine: 1965, short for fanzine (1949), from fan + suffix abstracted from magazine.
zinfandel: 1896, "red or white dry California wine," origin uncertain; used earlier as the name of the grape from which it was made (1880). The wine itself is said to have been known in U.S. since 1829. Some wine experts suggest a corruption of the Austrian grape name Zierfandler, though these grapes are not related to those of zinfandel. E.g. this article:
The similarity in the names Zinfandel and Zierfandler arouses some speculation. Modern vine identification systems did not yet exist in 1829, so it is conceivable that the cuttings George Gibbs imported to the USA had never been correctly identified in Austria.
zing (n.): 1911, "high pitched sound," 1918, of echoic origin. Slang meaning "energy, zest" is attested from 1918. Zinger "cruel quip" first attested 1970.
zinnia: genus of herbs of the aster family, 1767, from Mod.L. (Linnæus, 1763), named for Ger. botanist Johann Gottfried Zinn (1729-59)
Zion: O.E. Sion, from Gk. Seon, from Heb. Tsiyon, name of a Canaanite hill fortress in Jerusalem captured by David and called in the Bible "City of David." It became the center of Jewish life and worship. Zionism "movement for forming (later supporting) a Jewish national state in Palestine" first attested 1896, from Ger. Zionismus (from Zion + L.-derived suffix -ismus), first recorded 1886 in "Selbstemancipation," by "Matthias Acher" (pseudonym of Nathan Birnbaum).
zip (v.1): "move rapidly," 1852, of echoic origin. Zippy is first attested 1904. Zip gun "homemade pistol" first recorded 1950.
zip (adj.): 1963, in U.S. postal ZIP code, an acronym for Zone Improvement Plan, no doubt chosen with conscious echo of zip (v.1).
zip (n.): "zero," 1900, student slang for a grade of zero on a test, etc.; of unknown origin; cf. zilch.
zip (v.2): "to close or fasten by means of a zipper," 1932, back-formation from zipper.
zipper: 1925, probably from zip (1). The trademark taken out on the name that year applied to a boot with zippers, not to the "lightning fastener" itself, which was at first called a zip.
Zippo: proprietary name of a brand of cigarette lighter, patented 1934 by Zippo Manufacturing Co., Bradford, Pa.
zircon: 1794, from Ger. Zirkon (cf. Fr. jargon, It. giargone), from Arabic zarqun "cinnabar, bright red," from Pers. zargun "gold-colored," from Avestan zari- "gold-colored," from zar "gold." Zirconium, metallic chemical element, first attested 1808, coined by Ger. chemist Martin Heinrich Klaproth (1743-1817) in 1789; so called because it was found in zircon.
zit: "acne pimple," 1966, originally U.S. teenager slang, of unknown origin.