- zooxanthellae (n.)
- 1889, from German (Brandt, 1881), from comb. form of Greek zoion "animal" (see zoo) + xantho- (see xanthous) + Latin suffix -ella.
- zori (n.)
- 1823, from Japanese zori, from so "grass, (rice) straw" + ri "footwear, sole."
- Zoroastrian
- 1743, from Zoroaster, from Latin Zoroastres, from Old Persian Zarathushtra, 6c. or 7c. B.C.E. Persian religious teacher. The name appears to be literally "whose camels are old," from *zarant "old" (cognate with Greek geron, genitive gerontos "old;" see gerontology) + ushtra "camel."
- Zoroastrianism (n.)
- 1854, from Zoroastrian + -ism.
- zorro (n.)
- 1838, "South American fox-wolf," from Spanish zorro, masc. of zorra "fox," from Basque azaria "fox." The comic book hero, a variation on the Robin Hood theme set in old Spanish California, was created 1919 by U.S. writer Johnston McCulley (1883-1958).
- zoster (n.)
- kind of seaweed, c.1600, Latin, from Greek zoster "girdle," from zonnynai (see zone (n.)). Meaning "shingles" is from 1706; in the literal sense, "a belt or girdle, especially for men," from 1824.
- zouave (n.)
- 1848, from French, from Arabic Zwawa, from Berber Igawawaen, name of a Kabyle tribe in Algeria, from which the French light infantry troops of that name were originally recruited in 1831.
- zouk (n.)
- Creole French, "party," from zouker "engage in unrestrained social activity."
- zounds
- c.1600, oath of surprise or anger, altered from (by) God's wounds!
- zowie
- expression of astonishment, c.1913.
- zucchetto (n.)
- 1853, from Italian zucchetta "a cap," originally diminutive of zucca "gourd, head," perhaps from Late Latin cucutia, of unknown origin.
- zucchini (n.)
- 1929, from Italian, plural of zucchino, diminutive of zucca "gourd, squash," perhaps from Late Latin cucutia, which is of unknown origin.
- Zulu
- 1824, a native name.
- Zurich
- German Zürich, ultimately from Celtic root *dur- "water."
- zwieback (n.)
- 1894, from German Zweiback "biscuit," literally "twice-baked," from zwei "two, twice" + backen "to bake;" loan-translation of Italian biscotto (see biscuit).
- Zwinglian
- 1532, after Ulrich Zwingli (1484-1531), Swiss Protestant reformer.
- zydeco (n.)
- 1949, perhaps from Creole French pronunciation of French les haricots "the beans," part of the title of a popular dance tune ("les haricots sont pas salés").
- zygoma (n.)
- plural zygomata, 1680s, Modern Latin, from Greek zygoma, from zygon "yoke" (see jugular).
- zygomatic (adj.)
- 1709, from Latin zygomaticus, from Greek zygoma (see zygoma).
- zygote (n.)
- 1880, coined 1878 by German cytologist Eduard Strasburger (1844-1912), the widespread attribution to William Bateson being apparently erroneous; from Greek zygotos "yoked," from zygon "yoke" (see jugular).
- Zyklon (n.)
- 1926, from German Zyklon, commercial name of a type of hydrogen cyanide, of unknown etymology, but it is the usual German form of the word cyclone. Originally used as a pesticide and fumigant.
- zymurgy (n.)
- branch of chemistry which deals with wine-making and brewing, 1868, from Greek zymo-, comb. form of zyme "a leaven" (from PIE root *yeue-; see juice) + -ourgia "a working," from ergon "work" (see urge (v.)).
The last word in many standard English dictionaries (and this one); but in the OED [2nd ed.] the last word is zyxt, an obsolete Kentish form of the second person singular of see (v.).