1. The twenty-fourth letter 
and nineteenth eonsonant- 
sigi! in the English alpha- 
bet. In the Latin alphabet, from 
which it comes to ours, it followed 
next after U or r (which were then 
only one letter: see U\ and was 
till a late date the last letter in 
that alphabet, till Y and X (see 
those letters) were finally adde<] 
from the Greek to represent pe- 
culiar Greek sounds. The sij;n X was a Greelc addition 
to the Phenician alphabet ; it had in early Greek use a 
divided value : in the eastern alphabets, that of kh (besides 
the sijnis for ph and th) ; in the western, that of A->f (besides 
the signs forjwand tuttrtU). The fornn-rof thetwo<^ante 
afterward t*> be the universally acceptetl value in Greece 
Itself ; while the latter was t-arried over into Italy, and so 
became Roman, and was passed on to us. Hence our .V lias 
in general the Latin value kg; but as initial (almost only in 
words from the Greek, and there representing; a dilferent 
Greek character, the k*fi) we have reduced it to the z-sound, 
as in Xerxes, xanthous. In many words also, especially 
auiongthosc l>eginniuK with ex, it is maile sonant, or pro- 
nounced as gz. Tlie accepted rule (or this is that the gz- 
•ound is given after an unaccented before an accented 
Towel, as in ex'rt, exilic {egzert, egzUic), over against <'x<t- 
eue, f^xUe {ekxercize, eksil). But usage does not follow the 
rule with exactness, and many cultivated speakers disre- 
gard the distinction altogether, pronoun<-ing everywhere 
alike ks (or kz). In any case, the sign X is superftuous in 
English, as it wjis in I^atin and in Greek; it denotes no 
Bound which is not fully provided for otherwise. In Old 
English it was sometimes used for «/i, as in xal — shall. 
2. As a numeral, X stamls for ten. when laid 
horizontally (X), it stands for athousand, and with a dash 
over it (X). it stands for ten thousand. 
3. As an abbreviation, X. stands for Chri.it, as 
in Xu. (Christian), Xmas.(Christmas). — 4. As a 
.symbol: (a) Inoniitli., in myological fonnulas, 
the symbol of the semitendinosus muscle. .1. 
H.Garrod. (h) Inmath.: (1) [/.c] In algebra, 
the first of the unknown tiiiantities or variables. 
(2) [I. c] In analytical geometry, an abscissa 
orotherreetilinear point-cotinlinate. (.'!) In me- 
chanics, the component of a force in the direc- 
tion of the axis of x. — 5. Originally, a mark on 
brewers' casks; hence, a name given to ale of 
a certain quality. Compare XX, XXX Xn 
function. See/Hmrfton. 
xanorphica (za-n6r'fi-ka), II. A musical in- 
strument, resembling the harmonichord ami 
the tetrachordon, invented by RoUig in 1801. 
the strings of which were sounded by means of 
little bows. 
Xantharpyia (zan-thiir-pi'i-ii), ». [Nl>. (J. E. 
Gray), < Gr. f«i*i5<;, yellow, -I- XL. Hiirjii/i<i, 
q. v.] A gt'iiua of I'IcroiiDtlidx. X. iimjiUxicitii- 
Aata is a fruit-bat of the Austroraalayan sub- 
region. 
zantharsenite (zan-thiir'se-nit), «. [< Gr. fui- 
«<«;, yellow, -t- E. (irsenite.'\ A hydratetl arsenate 
of manganese, oceurringin sulphur-yellowmas- 
sive forms. It is found in Sweden, and is re- 
lated to chondrarscnite. 
Xanthate (zan'that), ». l<xaiith(ic) + -afel.] 
A salt of xanthic acid. 
Xanthein (zan'the-in), n. [< Gr. ^ai'dir, yellow, 
+ -<'-in''.\ That part of the yellow coloring 
matter in flowers which is soluble in water, as 
ilistinguished from lanthin, which is the insol- 
uble part. 
xanthelasma (zan-the-las'mii), «. [NL., < Gr. 
inMir, yellow, + i/aa/ia, a plate.] Same as 
xidiIIkiiiki. 
Xanthia (zan'thi-a), n. [NL. (Ochsenheimer, 
1H1(5;, < Gr. fai'flor,"yellow.] A genus of moths, 
of the family Ortlio-tii/lie, having slender porreet 
palpi, and mostly yellow or orange fore wings 
undulating along their exterior border. Itcom- 
5risesalH>ut :U) species, ancl is represented in Europe, Asia, 
orth an<l .South Americii, and the West Indies, .r. /ul- 
voffo is the sallow-niotb of Europe. Its larva feeds when 
young on catkins of willo>v, later on bramt)le and jdan- 
Uin. 
Xanthian (zan'thi-an). II. [<(ir. Siii'flof, Xan- 
thus (see <lef.).] fjf or belonging to Xanthus, 
an ancient town of Lycia in Asia Minor.— Xan- 
thian sculptures, a larwe collection of sculptures, chiefly 
sepulchral, from .Xanthus and the neighboring region, jire- 
■erved in the British Museum. The collection includes 
tlie reliefs from the so-called Harpy tomb. See Harjnt 
monument, under harpif. 
xanthic izan'thik),o. [< Gr. iavOor, yellow, -I- 
-/(■.] Tending toward a yellow color: of or 
relating to xanthin; yellow, referring to the 
color of the urine.— Xanthlo acid, the general name 
of the esters or ether-acids of tiiiosulphocarbonic acid, 
as ethyl xauthic acid, C.SO.C2H5.SH, a heavy, oily li- 
quid with a penetrating smell and a sharp, astringent 
taste, many of whose salts have a yellow color. — Xanthlc 
calculus, a urinary calculus composed in great part of 
xanthin. — Xanthic flowers, flowers which have yellow 
for their type, and are capable of passing into red or white, 
but never into blue. Those flowers of which blue is the 
type, and which are capable of passing into red or white, 
but never into yellow, have been termed cyanic Jtou'erii. — 
Xanthic oxld, xanthin. —Xanthlc-oxld calculus. Same 
us xanthic calculug. 
xanthidt (zan'thid), «. [< Gr. faryof, yellow, 
+ -(V/-.J A compound of xanthogen. 
xanthin, xanthine (zan'thin), h. [Also xanthin; 
< (Jr. fai^df, yellow, -f- -hi'^, -iiiii-.'\ One of sev- 
eral substances, so named with reference to 
their color. Especially— (a) That part of the yellow 
coloring matter of flowers which is insoluble in water, {h) 
The yellow coloring matter containetl in madder, (c) A 
gaseous product of the decomposition of xanthates. (rf) 
A complex body, 0511,1X400, related to uric acid, occni'- 
ring normally in small quantity in the blood, urine, and 
liver, and occa.sioiial]y in urinary calculi. It is a white 
dimorphous lx>dy,aiui combines with both acids and bases. 
— Xanthin calculus. Same us xan/hic c^ilcMlu^. Sec 
xanthic. 
xanthinuria (zan-thi-nii'ri-a), 11. [< x<intlun + 
( ir. (irfKif, urine.] The excretion of xanthin in ab- 
normal ((uantity in the urine. Also xaiithuriii. 
Xanthispa(zan-this'pa),«. [NL. (Baly, ISog), 
< Gr. iaMjr, yellow, 4- NL. Hispti, q. v.] A 
genus of leaf -beetles, of the family Cliri/so- 
iiiclitlse, erected for the single species .Y. riiiii- 
foitlr.v, from Cayenne. 
Xanthitane (zaii'thi-tan*, «. [< Gr. Sni'flor, yel- 
low, + (l)ifiiii(ic).'\ An alteration-product of 
the sphene (titanite) from Henderson count}'. 
North Carolina. In com])osition it is analogous 
to the clays, but contains chiefly titanic acid 
instead of silica. 
xanthite (zan'thit), «. [< (ir. iai'Ooi;, yellow, 
+ -ilr-.J A variety of vesuviiinite foun<l in 
limestone near Amity, New York. 
Xanthium (zan'thium). II. [NL. (Tonniefort, 
1700; earlier by Lobel, lo76), < (Jr. irivlhai-, a 
plant, said to be -Y. ■•itniiiKiriKm, and to have 
been so named because its infusion turned the 
hair yellow: < invtlor, yellow.] A genus of com- 
posite plants, of the tribe Ifclidiithoiilia- and 
subtribe .iiiilirosUie. Itischarac^terizedby unisexual 
flower.beads, the male with a single row of separate bracts. 
leaves which ai'c lobed and closely tomentose, or arc coarse- 
ly toothed and greenish- The small monoecious flower- 
heads are solitary or clustered in the axils; in the fci-tile 
heads the fruit fornjs n large spiny bur containing the 
aclienes. The species are known as cockle-bur, or as clot- 
hur ; 3 occur in the United States, only 1 of whicli is a na- 
tive, X. Caiutdfinse, which varies near the coast and the 
Great Lakes to a dwarf variety, echinatum, known as sea- 
burdock; of tlic others, ,V. «i_dnosuin, the spiny clot-bur, 
tliiuight to be a native of Chili, is aimed with slender yel- 
lowisll trifld spines in the axils ; and X. struvmrium is the 
common species of Euroju'. In Euglaiul it is known iis 
ditch-bur, Imrweed, louse-bur, and small burdock. 
xanthiuria (zan-thi-fi'ri-ii), «. Same as xaii- 
tliiitiiriii. 
Xantho (zan'tho), J). [NL. (Leach, 1815), < Gr. 
faiW(if, yellow.] A genus of brachyurous crus- 
taceans, of the family Cdturida', with numerous 
species. Also Xanthus. 
xanthocarpous (zan-tho-kiir'piis), a. [< Gr. 
^avHur, yellow, -I- Kap-ur, fruit.] In hot., hav- 
ing yellow t'rnit. 
Xanthocephalus (zan-tho-sef'a-his), n. [NL. 
(Bonaparte, I80O), < Gr. im'ffoc, yellow, -f utipa/J/, 
head.] A genus of /ctovV/a', or American black- 
birds, having as type the common yellow-headed 
blackbird of the United States, first described 
by Bonaparte in 1825 as IHrruf! icterocephttlus. 
and now known as A', icterocepliiihis. This large 
blackbird, of striking aspect, abounds in North America 
Upper I'art of the Steii 
Cockle-tiiir i 
with the Flower-he.Hdb and Leaves of 
i'itntltium stri/wrirtttm). 
, staniiiiate flow 
I*, pistillate flower: r 
pistill.ite flowers. 
olticre, inclosinK two 
the female armed with numerous hooked prickles. Twenty- 
oTie species have been described, perhaps to be reduced to 
four : they are mostly of uncertain, iierhaps of American, 
origin, but are ntiw widely naturalized throughout wann 
regions. They are coarse weedy anumtis witli alternate 
6997 
Vetlow-he.uieii Blatkhirii i-l',, ,////,/ v/Ai//,^r uUroirfhattts^, male. 
from Illinois, Iowa, and Wisconsin westward, exten<ling 
north into the IJritish i)ossessions, and south into Mexico, 
The male is jet-black, with the whole head and iteck 
Ipright-yellow, except the black lores and a black space 
about the base of the bill; there is a large white wing- 
patch, und usually there arc a few yellow feathers on the 
thighs an,l vent. The length is from 111 to 11 inches, the 
extent lOA \o\l\. Tlie female is sinaller and chietiy brown- 
ish. This blackbiril nests in niarsliy places, and lays from 
three to six eggs of a grayi.sh-gieen color sjudted with 
reddish brown. Also called Xontliosvvius. 
Xanthochelus (zan-tho-ke'lus), II. [NL. 
((.'hevrohit, 1873), < Gr. faittir, yellow, -1- j;//?/, 
a claw.] A genus of snout-beetles, of the fam- 
ily Ciirriilioiiiila! and subfamily Clcmiiiiie, hav- 
ing wings and somewhat prninose elytra. It 
contains less than a dozen species, distributed 
from Egypt to Siberia. 
Xanthochlorus (zan-tho-kl6'rns), n. [NL. 
(Locw, 1857), < Gr. imOue, yellow, + x''->l'k, 
greenish-yellow.] A genus of dipterous in- 
sects, of the family ItiilifhtijuKUihv. ooniprising 
4 small rust-colored sjiecies with yellow wings, 
of which :! are European and 1 is North Amer- 
ican, l.cptnpiis is a synonym. 
Xanthochroa (zan-tIio'k'ro-a),H. [NL.(S(dimidt, 
I84G),< (.Jr. -^niOiixpimi:, with yellow skiii,< ^uiMr, 
yellow, + xpoiii, X9<'"^> tln^ skin.] A genus of 
beetles, of the family (F.ili iiiiriiJa', conijirisiiig 7 
species, of which ;! are European, I is South 
American, and ,'! are North American. They are 
small slender beetles with cnntiguoiis midille coxa-,' one- 
spurred front tibia), and deeply eiimrginate eyes. 
Xanthochroi (zan-thok'10-i). «. /</. [NL.. jil. 
of xiiiitliiK-liroii.f : see jiiiithorhniii.'i.] In cth- 
iioL, one of the five gi'oups into which some 
