Tetradecapoda 
6256 
to Artlirostntcii. The multiarticulate cephalo- 
thorax has seven thoracic segments, each of 
which bears a pair of legs. The order includes 
the isopods and amphipods. 
tetradecapodous (tet"ra-de-kap'o-dus), a. [< 
tetradecapod + -ous.] Same as tetradecapod. 
[< tetragon + 
tetrahedron 
one who has married four times, < Gr. rerpa-, tetragonous (te-trag'o-nus), a. 
four, + yAfiof, marriage. Cf. digamy.] A fourth -ous.] Same us tetragonal. 
marriage; marriage for the fourth time. [Rare.] tetragram (tet'ra-gram), n. [< Gr. 
He [Symeon Magisterj says that the lawfulness of te- P v > a word of four letters (not found in the 
tragamy was believed to have been revealed to Euthymius. sense of a figure of four lines'), < rtrpa-, four, 
Robertson, Hist. Christ. Church, IV. 3. + ypd/tfta, a line, letter : see granfi.] 1 . A word 
tetradiapason (tet"ra-dl-a-pa'zon), . [< Gr. tetragenous (te-traj'e-nus), a. [< Gr. rerpa-, of four letters. 2. In geom., a figure formed 
Ti-Tfia-, torn; + E. diapaso'ii.] In mvsi-e, the in- four, + -yevfc, < yiyveoDai, be born: see -gen. -ge- b . v four "ght lines. 
teryal of four octaves, or a twenty-ninth. Also nous.] In bacteriology, giving rise to square Tetragrammaton(tet-ra-gram'a-ton), n. [<Gr. 
octave, groups of four, as micrococci which divide in ri> rtTpayp^tftarmi, a word of four letters, < rerpa- 
two planes at right angles, and whose newly }p<W<zroc, _? fou . r letters : see tetragram.] A 
formed cells remain attached to one another. 
In investigating the etiology of tuberculosis, E. Koch found 
in a cavity of the lungs, in a case of phthisis, a peculiar mi- 
crococcus in square groups of four, enveloped in a trans- 
parent capsule. This micrococcus was named Micrococ- 
cus tetragenws (whence the term tetragenous). 
complex of four letters : applied to the mystic 
name Jehovah (see Jehovah) as written with four 
Hebrew letters, and sometimes transferred to 
other similar combinations. 
When God the Father was pleased to pour forth all his 
glories, and imprint them upon his holy Son in his exal- 
tation, it was by giving him his holy name, the Tetragram- 
maton, or Jehovah made articulate. 
Jer. Taylor, Works' (ed. 1835X I. 744. 
It follows from all this that the true representative of 
the Tetragrammaton is the name itself, whether the form 
preferred be Jahveh, or the venerable and euphonious 
e fourth square, < Gr. rerpdywof/four-cornered; square, . Nineteenth Century, XX. 97. 
n eccles. neu t. rerpdyuvov, a square, < rerpa-, four, + vuvla, Wtragyn (let ra-jin), n. [< Gr. rerpa-, four, + 
> < a female (in mod. hot, a pistil).] In Jo*., 
The constituents of the colony turned out to be a tetra- 
genous microbe quite distinct from the plain atmospheric 
micrococcus with which he had thought it could be iden- 
tified. Science, XI. 283. 
called quadruple diapason, quadruple 
and quadruple eighth . 
tetradic (te-trad'ik), a. [= OF. tetradique; < 
LGr. rerpa&Kdf, tetradic, < Gr. rerpdf (-a(!-), a tet- 
rad.] 1. In anc.pros. : (a) Comprising four dif- 
ferent rhythms or meters : as, the tetradic epip- 
loce. (6) Consisting of pericopes, or groups 
of systems each of which contains four unlike 
systems: as, a tetradic poem. 2. Of or per- 
taining to a tetrad. Also tetratomic. 
tetradite (tet'ra-dit), n. [< tetrad + -ite'*.] 
One who has soine special relation to the num- tetragon (tet'ra-gon), n. [< F. tetragone = Sp. 
ber four, (a) One who regarded four as a mystic num- tetrdgono = Pg. It. tetragono, < L. tetragonum, a 
ber. (6) Among the ancients, a child born in the 
month or on the fourth day of the month, (c) In - 
S']TQuarUe V cTm n an eSfOUrg d8intheg d ' <<0 angle, corner.] I/In geom.; a figure having ... -x- , , 
tetradrachm ~ra-dram), n. [< L. tetra- >nr angles; a quadrangle; a quadrilateral.-^ ^l^l^te^awn^ ^ PI8tUS; * 
drachmum, < Gr. nrpUpaxpZ, a piece of four 2. In astral., an aspect of two planets with re- ^-trkWia. '?' nl rm 
gard to the earth when they are distant from ietragynia (tet-ra-jm i-a), n. pi. [NL.: see 
each other 90, or the fourth part of a circle ; f r W-J ., An . ? rder of plants in several of the 
quartile aspect; square. classes in the Linnean system, comprehending 
tetragonal (te-trag'o-nal), . [< tetragon + -al.] * hose P lants which have four P isti 's. as the 
1. In geom., pertaining to a tetragon; having . ? ^ ' 
four angles or sides. 2. In bot. and eool., four- tetragyman (tet-ra-jm i-an), i, [< tetragyn + 
angled; having four longitudinal angles. 3 '"'"] In bot -' navin g the characters of the 
Square; quartile. Sir T. Browne.- Tetragonal J2*" W " te; tetragynous. 
spheroid, a tetrahedron with isosceles faces. Telrag- tetragynous (te-traj i-nus), a. [ < tetragyn + 
onal stem, a stem that has four sides, as in many Labi- -Otis.] Having a gynoacium of four carpels. 
atse. Tetragonal system, in crystal., that system in tetrahedral (tet-ra-he'drall a TAlsn tftrnp 
which the three axes are at right angles to each other, but d r< d-<tftrfil}f<lr,n,+ nl \ 1 Pfirtainl 
the two equal lateral axes differ in length from the ver- Ul <> tetranearon-r -al. ] 1. Pertaining to a 
ticalaxis. See crystallography. Also dimetric, quadratic, tetrahedron. 2. In crystal.: (a) Having the 
monodimetric, etc. form of the regular tetrahedron. (6) Pertain- 
tetragonel (te-trag'o-nel), a. [Heraldic F.: ing or relating to a tetrahedron, or to the system 
see tetragonal.] In her., represented as a four- of forms to which the tetrahedron belongs : as, 
sided solid shown in perspective : thus, apyra- tetrahedral hemihedrism (see hemihedrism). 
mid is distinguished from a pile or point by be- 
ing represented in perspective, two sides show- 
ing, and is often blazoned a tetragonel pyramid. 
Tetragonia (tet-ra-go'ni-a), n. [NL. (Lumfeus, 
1737),<Gr.rerpoyiJwa,the'spindle-tree(socalled . . -. -. 
from its square fruit), < Tcrpayume, square: see tetrahedrally (tet-ra-he dral-i), adv. 
tetragon.] A genus of plants, of the order Fi- rahedral form. Also tetraedrally. 
coidete, distinguished from Mesembryanthemum, tetrahednte (tet-ra-he drit), . 
the other genus of its tribe, Mesembryese, by 
drachmas, < re- 
rpa-, four, + 
dpaxpii/, a drach- 
ma : see drach- 
ma.] A silver 
coin of ancient 
Greece, of the 
value of four 
drachmas. See 
drachma. 
Silver tetra- 
drachms of ^Enos. 
R. P. Knight. 
tetradymite 
(te-trad'i-mit), 
n. [< Gr. re- 
rpdrfv/^of, four- 
fold, + -ife2.] 
Native bismuth 
telluride, con- 
taining also 
some sulphur, a 
mineral occur- 
ring in foliated 
masses of a pale 
steel-gray color 
and brilliant 
metallic luster. 
Also called tel- 
luric bismuth, 
tellur - bismuth, 
Tetrahedral angle, in geom., a solid angle bounded or 
inclosed by four plane angles. Tetrahedral coordi- 
nates. See coordinate. Tetrahedral garnet, helvite : 
so called because, while related to garnet in composition, 
it occurs in tetrahedral crystals. Tetrahedral group 
See group*. 
In a tet- 
[< tetrahedron 
+ -ite't.] A mineral often occurring in tetrahe- 
its apetalous flowers, it includes about 20 species, d l al JV ai ^ (whence the name), also massive, 
mainly natives of the Cape of Good Hope, with others in t an iron-black color and brilliant metallic lus- 
Keverse. 
Tetradrachm of Athens, about 220 - 196 
B. c. British Museum. (Size of the ori- 
ginal.) 
and bornine. 
tetradymous (te-trad'i-mus). a. [< Gr. .. 
<5i)/iof, fourfold, < rerpa-, four: see tetra-.] In 
bot., having every alternate lamella shorter than x 
the two contiguous to it, and one complete la- tetragonismt (te-trag o-mzm), n. 
, 
eastern Asia, Australia, and South America. They are 
somewhat fleshy herbs or undershrubs with weak or pros- 
trate stems, bearing alternate entire leaves, and axillary 
greenish-yellow or reddish flowers. The fruit is a drupe 
or nut, often prominently winged, angled, or horned, con- 
taining a bony stone with from one to nine one-seeded 
cells. By Lindley the genus was made the type of a former 
order Tetragoniacess. See Australian and New Zealand 
spinach (under spinach), and compare fat-hen and soda. 
ter. It is essentially a sulphid of copper and antimony, 
but the antimony may be replaced by arsenic or less fre- 
quently by bismuth, and the copper may be replaced by 
silver (in the variety freibergite), mercury (in the variety 
schwatzite), also iron, zinc, lead, and in small amounts 
cobalt and nickel. It is commonly called Fahlerzm Ger- 
many (whence the English fahl-are). It is sometimes an 
important silver ore. 
tetrahedroid (tet-ra-he'droid), n. [< tetrahe- 
dron + -oid.~\ A quartic surface the 
, ^-UL^CUC ia - .- . [NL- tetra- dron + -oid.] A quartic surface the envelop 
mella terminating a set of every four pairs of O ontsmus (John Bernoulli, 1696), < tetragon + of a quadric surface touching eight given lines ; 
short and long: said of an agaric ; also, havine m *l w ^ The 1 ua( irature of any curve. a surface obtained by a homographic transfer- 
tf\.i*. n^llr. ^.. , I-* _ . .1 TT " I OT.1*Q tftVnnna fi-cli--*n-m\ r nn*\c.\ TXTT ;O:.. Ai _ J.T 4. . -rr 
Henslow. 
W. 
rag 
. Jardme, 
four cells or cases combined. 
Tetradynamia (tefra-di-na'mi-a), n.pl. [NL., 
The fifteenth class in the Linnean system"fom- ^ ial - barbets ' belonging to the American Capi- the sixteen double planes pass'by'fours "aquar- 
onops (tet-ra-go'nops), M. [NL. (Sir 
rdme, 1855), < Gr. rcrpdyuvoc, square, 
f aee.] A remarkable genus of scanso- 
mation of the wave-surface ; a Kummer's sur- 
face whose sixteen nodes lie in fours upon the 
faces of a tetrahedron through whose summits 
prehending those plants which bear hermaph- 
rodite flowers with six stamens, four of them 
longer than the other two. it was divided into 2 
orders Siticvlosa, of which the common garden-cress and 
shepherd s-purse are examples, and SUiauosa, of which the 
mustard and cabbage are examples. AU the plants of this 
class are now included in the natural order Cntdfene. 
tetradynamian (tefra-di-na/mi-an), a. [< 
Tetradi/namia + -an.] 'In bot., having the char- 
acters of the Tetradynamia; tetradynamous. 
tetradynamous (tet-ra-din'a-mus), a. [< Gr. 
rerpa-, four, + Svva/ucj' power. Cf. Tetradyna- 
mia.] Having six stamens, four longer ar- 
ranged in opposite pairs, and two shorter, in- 
serted lower down: a relation found only in 
the flowers of Cruet/eras. See cut under stamen . 
tetraedral, tetraedron (tet-ra-e'dral, -dron) 
Same as tetrahedral, tetrahedron. 
Tetragameliae (tet"ra-ga-me'li-e), n.pl. [NL., 
< Gr. rerpa-, four, + yarffaoc, of a wedding, < 
yauoc, a wedding.] A division of rhizostoma- 
tous discomedusans having the four subgenital 
pouches distinct: opposed to Monogamelix. 
tetragamelian (tetra-ga-me'li-an), a. Per- 
taining to or having the characters of the Tet- 
ragamelise. 

tomnse. It is characterized by the peculiar metagna- 
ilsm of the beak, the under mandible having two angu- 
Tttragonops rhamphastinus. 
lar points which overlap the tip of the upper. There are 
tic surface cut by each of the planes of a tetra- 
hedron in pairs of conies in respect to which 
the three summits in this plane are conjugate 
points, and such that one of the points of inter- 
section of the conies (and therefore all) is a node 
of the surface : so named by Cayley in 1846. 
tetrahedron (tet-ra-he'drqn),n.; pi. tetrahedra, 
tetrahedrons (-dra,"-dronz). [Also tetraedron; 
= F. tetraedre = Sp. Pg. te- 
traedro, < Gr. rerpa-, four, + 
fSpa, seat, base.] A solid 
comprehended under four 
plane faces; especially, the 
regular tetrahedron, or tri- 
angular pyramid having its 
base and sides equilateral 
triangles. In crystallography and 
in geometry the tetrahedron is re- 
garded as a hemihedral form of the 
octahedron, four of whose faces 
form the plus, and the four alter- 
nate faces (two above and two be- 
low) the minus tetrahedron. The 
figures represent the tetrahedron 
in the position required to exhibit 
its relation to the octahedron. See 
hemihedral. Orthogonal tetra- 
2- . mi i . v.f.f*'*. *iw <uc rii'mim (irtn 
species, T. rhamphastinus of Ecuador and T. frantzi hedron a tetrahedron The" pairs of 
tetragamy (te-trag'a-mi), n.. [< MGr. rerpaya- & SJ% ^5?^J^1S& whose opposite edges are at right angles-mother words, 
Ilia, the marrying a 'fourth time, < *Tt~rpdyaftoc, 
tiveness of a toucan, is singularly variegated with black 
white, ashy, golden-brown, orange-red, and scarlet. 
the planes through these edges and the shortest line be- 
tween them are at right angles. Such a tetrahedron is die- 
