Triassic 
Keuper (see those words) are well-marked features of the 
geology. In the Alps, especially toward the eastern > inl 
of tin- range, the Trlawic it developed to very great thick- 
ness and in great. OOBplexity uf subgroups, each charac- 
terized liy ilh own peculiar assemblage of fossils. I his 
complexity is specially characterWi. -of the upper portion 
of the series. In England the line sepantliif uM Triasalc 
from the I'erinian is much less distinctly marked than It 
is on tin- Continent. What was formerly called the "New 
tted SiimlHtonr " is now divided, in accordance uitli pale- 
ontological and not lithological characters, into Permian 
anil Triassic. In the I'nited Stairs the Trliisslc plays an 
important part, but varies greatly in character in ili!t> i mi 
parts of tlie country. The sandstones of the Connecticut 
river valley and the continuation of the same formation 
to tlie south, through Pennsylvania and Virginia into 
North Cjirolina, coiiMtitute li very marked feature of the 
geology of the Atlantic belt of States, containing various 
fossil plant* lesemliliriK ttiosc found in F.urope on the 
same horizon, and especially characterized by tracks of 
vertebrates, while remains of their liony skeletons are ex- 
tremely rare. The Triassic of the Hocky Mountain region 
is also an important formation (see Red bed*, under r-</ 1 ) ; 
and that of the western region of the tireat Basin, of 
the Sierra Nevada, and of the ranges further north near 
the coast is also extremely interesting, resembling very 
closely in the character of its fossils the Triassic of the 
eastern Alps. The most striking feature of the flora of the 
Triassic Is the predominance of the cycads, hence the 
period of deposition of this division of the series has 
sometimes been called the " age of cycads." The earliest 
remains of mammalian life are found In the Triassic, in 
the form of small marsupials. In the Alpine Triassic, both 
in the Alps and on the western coast of North America, 
there Is a most remarkable commingling of Paleozoic and 
Mcsozolc types of cephalopods. 
triatic (tri-at'ik), a. [< L. tres (tri-), three, + 
-atic 1 .] Forming three angles: only in the 
phrase triatic stay. See stay 1 . 
triatomic (tri-a-tom'ik), a. [< Or. rpeif (rpt-), 
three, + &TOIMV, atom: sec nlom, atomic."} In 
chem.: (a) Consisting of three atoms: applied 
to the molecules of elements where the atoms 
are of the same kind: as, a triatomic element; 
or to compounds where the atoms are unlike : as, 
triatomic molecules. (6) Same as trivalent. (c) 
Having three hydroxyl groups by which other 
atoms or radicals may be attached without al- 
tering the structure of the rest of the molecule : 
thus, glycerin is called a triatomic alcohol. 
triaxal (tn-ak'sal), a. [< L. tres (tri-), three, 
+ n.ri.i. axis, + -a/.] Having three axes : as, tri- 
axal coordinates. 
triaxial (tri-ak'si-al). a. [< L. tres (tri-), three, 
+ H.ii*. axis, + -a/.] Having three axes, as 
some sponge-spicules. 
Although they [spicules] are ouadrlradlate, they are 
still only triaxial. Micrw. Science, N. S., XXXII. 7. 
triaxon (tri-ak'spn), a. and w. [< Gr. rpeZf (rpi-), 
three, + &fuv, axis.] I. a. Triaxial.as a sponge- 
spicule; having three axes diverging from a 
common center, resulting from linear growth 
from a center in three directions at an incli- 
nation of 120 to one another. See cut under 
gpongc-spicule. 
U. . A regular figure of three axes diverg- 
ing from a common center, as a sponge-spicule 
with three such axes. 
Triaxonia (tri-ak-so'ni-a), n.pl. [NL.: see tri- 
axon.] Triaxon sponges as a subclass of cal- 
careous sponges with simple canal-system and 
triaxon spicules. 
triaxonian (tri-ak-so'ni-an), a. Same as tri- 
axon. 
A triaxonian star with nve or six rays. 
Amer. Nat., XXI. 988. 
tribal (tri'bal), a. [< Mbr + -al.] 1. Of or 
pertaining to a tribe ; characteristic of a tribe : 
as, tribal organization ; tribal customs; a tribal 
community. 
The old tribal divisions, which had never been really ex- 
tinguished by Roman rule, rose from their hiding-places. 
Stubbs, Const. Hist, i 28. 
2. In Itiol., of or pertaining to phvla or other 
broad divisions of the animal kingdom : as, tri- 
bal history (that is, phylogeny, as distinguished 
from germ-history or ontogeny). Hatchet. 
tribalism (tri'bal-izm), n. [< tribal + -ism.] 
The state of existing in separate tribes ; tribal 
relation or feeling. 
No national life, much less civilisation, was possible un- 
der the system of Celtic trilmlinn, as it existed at least till 
the time of the Tudors. Kilinburi/h Ret., CLXIII. 443. 
The period of the Judges was one of entire tribalism, 
with little national union and continuous relapses into 
idolatry. The American, XVII. 104. 
tribally (tri'bal-i), adv. In a tribal manner; 
as or with reference to a tribe. 
It is probable that Professor Putnam is not Justified in 
concluding that the people of the two sections were <ri- 
Inllii Identical. Science, XV. 383. 
tribasic (tri-ba'sik), a. [< Gr. rpdc (rpt-), three, 
4- ;9<Svf, base, + -c.] In clicm., having three 
hydrogen atoms replaceable by equivalents of 
a base: noting some acids, 
406 
M6B 
trlbble (tril>'l), . [Perhaps :i corruption oi 
i-nhhl, . a >i,-\.-. ] In i>ii/,,r-i/iiiiint'.. a large hori- 
zontal frame in tin- loft or lining-room, with 
liiiirs or wires stretched across it. on which 
si is of paper are hung to drv. A 1 . //. l\ni</ltt. 
tribe (trib), n. [< MK. t,;i, H i'in pi. Irihu), < 
OF. trihii, F. iribu = Sp. tribu = Pg. tribu = It. 
li-iliii. tnli, i, < I,, tnliux. a divi-iou of the people. 
a tribe, in general the common people, the popu- 
lace; traditionally explained as orig. a 'third 
part' of the people (one of the three division- 
into which the Roman people were divided), 
and referred to tres (tri-), three (cf. dat. pi. tri- 
biis; Gr. dial, rpimri'f for r/xrri'f, a third part). 
Cf. W. tref, village; E. thorp, a village.] 1. 
In Bom. hi#t., one of the three patrician or- 
ders, or original political divisions of the peo- 
ple of ancient Rome, the Ramnes, Titles, and 
Luceres, representing respectively, according 
to tradition, the separate Latin, Sabine, and 
Etruscan settlements, having at their union 
equal representation in the senate, and retain- 
ing their distinctive names for several cent n 
ries. Hence 2. An^y one of the similar divi- 
sions of a race or nation common in antiquity, 
whether of natural or of political origin: as, 
the tribe* (QvAai) of Athens. Ethnical tribe* among 
the ancient* regarded themselves as enlarged families, 
and generally bore the name of some real or supposed 
common progenitor. Such were the twelve tribes of the 
Israelites, the tribes of the Dorians and other Greek noes, 
etc. The thirty (and afterward more) tribes Into which 
the plebeians in and around Rome were divided, after the 
formation of the patrician tribes, were based on locality ; 
and tribes nearly corresponding to castes have In some 
Instances been determined by occupation. 
Have you collected them by tribes f 
Shall., Cor., ill. 3. II. 
3. Specifically, a division of a barbarous race 
of people, usually distinguishable in some way 
from their congeners, united into a community 
under a recognized head or chief, ruling either 
independently or subordinately. in general the 
tribe, as It still exists among the American Indians and 
many African and Asiatic races, Is the earliest form of po- 
litical organization, nations being ultimately constituted 
by then- gradual amalgamation and loss of Identity In the 
progress of civilization. 
The characteristic of all these races [t'rallanj, when in 
the tribal state, is that the tribeg themselves, and all sub- 
divisions of them, are conceived by the men who compose 
them as descended from a single male ancestor. ... In 
some cases the Tribt can hardly be otherwise described 
than as the group of men subject to some one chieftain. 
Maine, Early Hist, of Institutions, pp. 65, 68. 
4. Any class or body of persons taken collec- 
tively ; any aggregate of individuals of a kind, 
either as a united body or as distinguished by 
some common characteristic or occupation. 
[Chiefly colloq.] 
Folly and vice are easy to describe, 
The common subjects of our scribbling tribe. 
Rracommon, A Prologue, spoken to the Duke of York at 
[Edinburgh. 
And then there flutter'd In, 
Half-bold, half-frightened, with dilated eyes, 
A tribe of women, dress'd in many hues. 
Tennyson, Qeraint. 
5. A family of cattle having a common female 
ancestor. Tribes of cattle are particular strains, taking 
their names usually from some particular cow appearing 
In the pedigrees, as the Princess or Duchess tribes of 
shorthorns. There is no absolute rule for naming a tribe, 
but it descends through the female line. 
6. In zool. andftof., a classificatory group of un- 
certain taxonomic rank, above a genus, and usu- 
ally below an order; loosely, any group or se- 
ries of animals: as, the furry, feathery, or finny 
tribes ; the cat tribe . IJnnssus distributed the vegeta- 
ble kingdom into three tribe*, namely monocotyledonous, 
dicotyledonous, and acotyledonous plants, and these he 
subdivided into gentes or nations. By other naturalists 
tribe has been used for a division of animals or plants In- 
termediate between order and genus. In botany this is 
the current and a very common use, the tribe standing 
below the suborder where that division Is present. Cnvler 
divided liis orders into families, and his families into tribes, 
including under the latter one or more genera. =8yn, 1-3. 
llaee. Clan, etc. See people. 
tribe (trib), v. t.; pret. and pp. tribed, ppr. 
tribing. [< tribe, n. J To distribute into tribes 
or classes. [Rare.] 
Our fowl, fish, and quadrupeds are well tribed by Mr. 
Willughby and Mr. Ray. Bp. Xicobon, Eng. Hist. Lib., L 1. 
tribelet (trib'let), . [< tribe + -let."] A little 
tribe ; a subordinate division or offset of a tribe. 
[Rare.] 
When a man marries a woman from a distant locality, he 
goes to her tribelet and Identifies himself with her people. 
Jour. Anthrop. Intl., XVHI. 250. 
tribesman (tribz'nian), . ; pi. tribesmen (-men). 
[< tribe's, poss. of tribe, + num.] A man belong- 
ing to a tribe ; a member of a particular tribe, 
or of the same tribe as the person speaking or 
referred to. 
tribroraphenol 
It was by taking a grant, not as elsewhere of land, hut 
of cattle, that th< i tile (lie man or vas- 
sal of an Irish 
J. R. Own, Making of Knglan.i 
tribespeople nriliz'pc'ph. ././. IVrson- con 
Htitiiting :i trilic: III.- members nf :i trihe. 
[Rare. | 
Me .tent me a list of the nniitt i of tribelpeople, 
Jmtr. Anthrop. I nit., XIX. 90. 
triblet (trib'let), n. [Also inliniilrt. inlnili-1, 
././,//,.- < OF. lrilx,i,l,l. 11 trililct, a dim. form, 
prob. < L. trilniln.< (ir. -/>' tn'/m; tlirci-poinl- 
ed instrument, a caltrop: we //'///.<...] 1. A 
mandrel used in forging tul^. nuts, ami ring's, 
iinil for other purposes. 2. The mandrel in a 
machine for making lead pipe. A'. //. Knii/lit. 
triblet-tubes (trii>'let-tut>/.). . /</. In i>ru 
lint/, tliin tubes fitted to slide in ami upon other 
tubes, usually of the same thickness of metal, 
as the tulies of microscopes, telescopes, and 
other optical instrument-. 
Triboloceratids (triVo-lo-se-rat'i-de), n. pi. 
[NL., < Gr. rpi/Jo/of, three-pointed (see Tribu- 
lus), + Kfpaf (nrpar-), horn, + -irfff.J A fam- 
ily of naiitiloid ccphalopods, having depressed 
whorls, fluted or hollow abdomen, the sides and 
the abdomen ridged lengthwise and the ridges 
often spinose, and the sutures with ventral, lat- 
eral, and dorsal lobes. Hyatt, Proc. Bost. 8oc. 
Nat. Hist., 1883, p. 293. 
triboluminescence (trib-^-lu-mi-nesViiH), . 
flrreg. < Gr. rpifieiv, rub, + E. luminescence.] 
Frictional luminosity; light emitted from bod- 
ies under the excitation of rubbing. 
According to the mode of excitation I distinguish Photo-, 
Electro-, Cheini , and Tribo-luminetcence. 
PhUot. Mag., 5th ser., XXVIII. 151. 
tribometer (tri-bom'e-ter), . [< Gr. rpi^eiv, 
rub, + fierpav, a measure.] An apparatus, re- 
sembling a sled, for measuring the force of fric- 
tion in rubbing surfaces. 
Tribonyx (trib 7 6-niks), n. [NL. (Du Bus, 1837), 
< Gr. Tpifotv, rub, + 6mf, claw.] A remarkable 
Trtfmr* vtmtralu. 
genus of Australian and Tasmanian gallinules, 
allied to fi'otornis : also called lirarJtyjttrallus. 
The leading species is T. rentralis. 
triboulet (trib'^-let), n. Same as triblet. 
tribrach 1 (tri'brak), n. [Formerly, as L., tri- 
brachyg, also tribrachus ; = F. tribraquf = Sp. 
tribraquio = Pg. tribraco, < L. tribrarhys, < Gr. 
Tpijtpaxi^, a tribrach, < rpcif (rpt-), three, + flpa- 
rf't, short: see brief.] In anc. proa., a foot con- 
sisting of three short times or syllables, two of 
which belong to the thesis and one to the arsis, 
or vice versa. It is accordingly trisemlc and diplailc. 
The tribrach was not used in continuous composition, but 
as a substitute for a trochee (the trochaic tribrach, c - - 
for -* I ~) or for an iambus (the iambic tribrach, ~ | & * tor 
~ I -). The name trochee or choree (trochjnui. choreuf) was 
given by some ancient authorities to the tribrach. Also 
tribrachyi. 
Never take an Iambus as a Christian name. A trochee 
or tribrach will do very well. 
Coleridge, Table Talk, Oct. 8, 1832. 
tribrach 2 (tri'brak), . [< Gr. rpri f (r/x-), three. 
+ .ipa^iuv, arm.] Same as tribrackuil. 
tribrachial (tri-bra'ki-al), n. [< tribrach? + 
-ial.] A three-armed figure or utensil ; specifi- 
cally, a three-branched flint implement occa 
sionally found. 
tribrachic (tri-brak'ik), a. [< tribrach 1 + -ic.] 
In one. pros. : (a) Consisting of three short times 
or syllables; constituting a tribrach. (6) Per- 
taining to a tribrach ortnbrachs; consisting of 
tribraclis. 
tribracteate (tri-brak'te-at), <j. [< L. tres(tri-). 
three, + brach-a, athin plate (bract): see bract.] 
In hot., having three bracts. 
tribromphenol (tri-brom-fe'nol), M. [< tri- 
+ brom(ine) + phenol.] A substance formed 
