xenonyoudaoicibaDictYouDict[xenon 词源字典]
xenon: [19] Xenon is etymologically the ‘strange’ gas. It was named in 1898 by its discoverer, the British chemist Sir William Ramsay. He adapted the term from the neuter form of Greek xénos ‘strange’, which may be a distant relative of English guest, hospital, host, etc, and is also the source of English xenophobia ‘fear of foreigners’ [19].
=> guest, hospital, host, xenophobia[xenon etymology, xenon origin, 英语词源]
xerox: [20] Greek xērós meant ‘dry’ (it may be the ultimate source of English elixir, and is perhaps distantly related to English serene and serenade). From it was derived in the 1940s the term xerography, which denotes a process of photographic reproduction that does not involve the use of liquid developers. And xerography in turn formed the basis of xerox, which was registered as a trademark for the process in 1952 by the Haloid Company of Rochester, New York (later renamed the Xerox Corporation).
=> elixir, serenade, serene
xylophone: [19] Etymologically, a xylophone makes ‘sounds’ from ‘wood’. The term was coined in the 1860s from Greek xúlon ‘wood’ (an allusion to the instrument’s tuned wooden bars) and the combining form -phone ‘sound’.
The entire entry for X in Johnson's dictionary (1756) is: "X is a letter, which, though found in Saxon words, begins no word in the English language." Most English words beginning in -x- are of Greek origin or modern commercial coinages. East Anglian in 14c. showed a tendency to use -x- for initial sh-, sch- (such as xal for shall), which didn't catch on but seems an improvement over the current system. As a symbol of a kiss on a letter, etc., it is recorded from 1765. In malt liquor, XX denoted "double quality" and XXX "strongest quality" (1827).

Algebraic meaning "unknown quantity" (1660 in English, from French), sometimes is said to be from medieval use, originally a crossed -r-, in that case probably from Latin radix (see root (n.)). Other theories trace it to Arabic (Klein), but a more prosaic explanation says Descartes (1637) took x, y, z, the last three letters of the alphabet, for unknowns to correspond to a, b, c, used for known quantities.

Used allusively for "unknown person" from 1797, "something unknown" since 1859. As a type of chromosome, attested from 1902 (first so called in German; Henking, 1891). To designate "films deemed suitable for adults only," first used 1950 in Britain; adopted in U.S. Nov. 1, 1968. The XYZ Affair in American history (1797) involved French agents designated by those letters.
x (v.)youdaoicibaDictYouDict
"cross out with an 'X'," 1942, from X.
X-ray (n.)youdaoicibaDictYouDict
1896, X-rays, translation of German X-strahlen, from X, algebraic symbol for an unknown quantity, + Strahl (plural Strahlen) "beam, ray." Coined 1895 by German scientist Wilhelm Conrad Röntgen (1845-1923), who discovered them, to suggest that the exact nature of the rays was unknown. As a verb by 1899. Meaning "image made using X-rays" is from 1934, earlier in this sense was X-radiograph (1899).
Mongol city founded by Kublai Khan, 1620s, anglicized form of Shang-tu. Sense of "dream place of magnificence and luxury" derives from Coleridge's poem (1816).
xanthic (adj.)youdaoicibaDictYouDict
"yellowish," 1817, from French xanthique, from Greek xanthos "yellow" (see xantho-).
also (incorrectly) Xantippe, late 16c., spouse of Socrates (5c. B.C.E.), the prototype of the quarrelsome, nagging wife. The name is related to the masc. proper name Xanthippos, a compound of xanthos "yellow" (see xantho-) + hippos "horse" (see equine).
before vowels xanth-, word-forming element meaning "yellow," from Greek xanthos "yellow" of various shades; used especially of hair and horses, of unknown origin. Used in scientific words; such as xanthein (1857) "soluble yellow coloring matter in flowers," xanthophyll (1838) "yellow coloring matter in autumn leaves." Also Huxley's Xanthochroi (1867) "blond, light-skinned races of Europe" (with okhros "pale").
xanthosis (n.)youdaoicibaDictYouDict
1857, Modern Latin, from Greek xanthos (see xantho-) + -osis.
xanthous (adj.)youdaoicibaDictYouDict
1829, "fair-haired and light-complexioned," from Greek xanthos "yellow," of unknown origin (see xantho-). But the word also was used in 19c. anthropology as "specifying the yellow or Mongoloid type of mankind" [Century Dictionary].
xebec (n.)youdaoicibaDictYouDict
"small three-masted vessel," favored by Barbary corsairs but also used in Mediterranean trade, by 1745, from French chébec, from Italian sciabecco, ultimately from Arabic shabbak "a small warship." Altered by influence of cognate Spanish xabeque, which shows the old way of representing the Spanish sound now spelled -j-.
xenelasia (n.)youdaoicibaDictYouDict
"prevention of aliens from settling in Sparta," Greek, literally "expulsion of foreigners," from xenelatein "to expel foreigners," from xenos "stranger" (see xeno-) + elatos, verbal adjective of elaunein "drive, drive away, beat out."
city in Ohio, from Greek xenia "hospitality, rights of a guest, friendly relation with strangers," literally "state of a guest," from xenos "guest" (see guest (n.)). Founded 1803 and named by vote of a town meeting, on suggestion of the Rev. Robert Armstrong to imply friendliness and hospitality.
xenial (adj.)youdaoicibaDictYouDict
"pertaining to hospitality," 1834, from Greek xenia (see Xenia) + -al (1). Related: Xenially.
before vowels, xen-, word-forming element meaning "strange, foreign; stranger, foreigner," from Greek xeno-, comb. form of xenos "a guest, stranger, foreigner, refugee, guest-friend, one entitled to hospitality," cognate with Latin hostis (see guest (n.)). "The term was politely used of any one whose name was unknown" [Liddell & Scott].
xenogamy (n.)youdaoicibaDictYouDict
1877, from xeno- + -gamy.
xenolith (n.)youdaoicibaDictYouDict
1894, from xeno- "foreign, strange" + -lith "stone."
xenon (n.)youdaoicibaDictYouDict
gaseous element, 1898, from Greek xenon, neuter of xenos "foreign, strange" (see xeno-); coined by its co-discoverer, Scottish chemist Sir William Ramsay (1852-1916); compare krypton.