trigonoid 
trigonoid (trig'o-noid), H. [< trignnl + -oiil.] 
A plane figure composed of three arcs of circles 
of equal radius, especially when two of these 
arcs subtend 60 and one 120. 
trigonoidal (trig-o-noi'dal), a. Like a trigonoid. 
trigonometer (tri'g-o-nom'e-ter), n. 
yuvov, triangle, + /urpov, measure.] 
ment for solving plane right-angled triangles 
by inspection. In the form shown in the figure, a 
graduated arm turns about one of the corners of a square 
6478 
trilithon 
base being formed by the striie acusticte, and the hypote- trilemma (tri-lem'a), . [NL., < Gr. -peif (rpi-). 
niise by the inner margin of the ala cinerea. Also called 
tuberculum hypoglosgi. Trigonum Lieutaudi, the tri- 
gonum of the bladder. Trfgonum vagi. Same as ala 
cinerea (which see, under ala). Trigonum vesiCSe. See 
def. (a). 
[<Gr. rpi- trigonyt (trig'o-ni), . [Cf. Gr. rpiyovia, the 
An iustru- third generation, < Gr. rpeif (rpt-), three, 
-yavia, production : 
birth or product. 
three, + Ai^u/ua, an assumption: see lemma 1 .'] 
1. In logic, a syllogism with three conditional 
propositions, the major premises of which are 
disjunctively affirmed in the minor. See di- 
lemma. 2. Hence, in general, any choice 
. ... between three objects. 
see -aony.l A threefold triletto (tri-let'to), it. [It., dim. of trillo: see 
friM a .] In music, a short trill. 
10 *> JO 40 SO go 70 ffO 
I 
Man is that great Amphybium in whom be trilinear (tii-lin'e-ar), a. [< L. tres(M-), three, 
Threed To^ntS^"ra S t'r P To. (A.**) + "T + .-?*' (f <'")] Composed or 
' consisting of three lines Trilinear coordinates 
trigram (tri gram), n. [= F. trigramme, < Gr. See coordinate. 
Tpeif(rpi-), three, + ypafj.ua, a letter.] Same as trilineate (tri-lin'e-at), a. [< L. trex (tri-), 
trigrapli. three, + linea, line, + -ofcl.] In zoiil., hav- 
trigrammatic (tri-gra-mat'ik), . [< Gr. rpi- ing three colored lines, generally longitudinal 
jpdfi/iaros, consisting of three letters, < rpelf ones. 
(T/>I-), three, + ypafiffa(r-), a letter.] Consisting trilingual (tri-ling'gwal), a. [Cf. F. Sp. Pg. 
of three letters or of three sets of letters. It. trilingue; < L. truinguis, in three languages, 
trigrammic (tri-gram'ik), n. [As frit/ram + < tres (tri-), three, + lingua, language: see lin- 
-ie.] Same as trigrammatic. 
trigraph (tri'graf), n. |X Gr. rpeif (rpi-), three, 
Trigonometer. 
graduated linearly parallel to adjacent sides, so as to form 
squares, and having outside of it a protractor. If the arm 
is not nicely centered, however, a detached rule would be 
preferable. 
trigonometric (trig/o-no-met'rik), a. [= F. 
trigonometrique = Sp. trigonometrico = Pg. It. 
_ " 
+~ypa<j>r/, a writing, < ypfyecv, write.] A combi- 
nation of three letters to represent one sound ; 
a triphthong, as eau in beau. 
trigyn (tri'jin), . [< Gr. rpelf (rpt-), three, + 
yvvr/, a female (in mod. bot. a pistil).] In bot., 
a plant having three styles; a plant of the or- 
der Trigynia. 
Trigynia (tri-jin'i-a), n.pl. [NL. : see trigyn.'] 
An order of plants in the Linnean system, dis- 
tinguished by the fact that the flowers have 
three styles or pistils, as in the bladder-nut. 
trigynian (tri-jin'i-an), a. [< Trigynia + -an.'} 
Belonging or relating to the Trigynia; trigy- 
nous. 
</'<"'.] Consisting of or expressed in three lan- 
guages. 
The much-noted Rosetta stone . . . bears upon its sur- 
face a trilingual inscription. Is. Taylor. 
trilinguar (tri-ling'gwar),. Same as trilingual. 
Trilisa (tril'i-sa), n. [NL. (Cassini, 1818): an 
anagram of Liatris.'] A genus of composite 
plants, of the tribe Eupatoriaccse and subtribe 
Adenostyleee. It is distinguished from the related ge- 
nus Liatns by its broad corymbose panicle of small flower- 
heads, with their membranous involucral bracts forming 
only two or three rows and but slightly unequal. The 2 
species are both natives of North America, growing in 
damp pine-barrens from Virginia south and west. They 
are erect perennials with alternate entire clasping leaves, 
those from the root very much elongated. T. (Liatris) 
odoratisnma is known as wild vanilla (which see, under 
vanilla), and is also called deer'i-tongue. 
trigontnftrico,\ NL. *trigonometricits,\ 
pelf (rpi-), three, + eSpa, a seat, + -7.] Hav- 
ing three sides ; three-sided. 
The upper face of the trihedral, proximal, and largest 
joint of the antennule presents an oval space. 
Huxley, Anat. Invert., p. 287. 
Trihedral angle, a solid angle formed by the concur- 
..-.1,1 ..ii.. .. ..iiii.ii. i ....... .. cfci ....... i. ... AAi&VAlUUlCU- , 'l_'l i rt T 
rical curve, a curve whose equation involves trigono- trinilate (tri-ni lat), a. [< L. tres (tri-), three, 
metrical and no higher functions. Trigonometrical + NL. hilum + -afel.] In bot., having three 
function, a singly periodic function with a real period ; },ji a OT , SPars as Sfipf i . having trirBn aner 
especially, the sine, cosine, tangent, or their reciprocals. ', , '" ' avin tnree a P er " 
- Trigonometrical survey, a survey by triangulation, tures, as a pollen-gram. [Rare.] 
the measurement of base-lines, and astronomical observa- tnhoral (tri-ho ral), a. [< L. tres (tri-), three, 
tions of latitude, longitude, and azimuth. A trigonomet- 
rical survey should be followed by a plane-table or other 
trigonometrical (trig"6-no-met'ri-kal), a. [< 
trigonometric + -a/.] Of or pertaining to trig- 
onometry; performed by or according to the 
rules of trigonometry Trigonometrical canon, 
a table of the numerical values 01 trigonometrical func- 
tions ; especially, a very extensive and fundamental table, 
from which smaller tables are extracted. Trigonomet- 
topographical survey ; it is also an important basis of or 
in three pairs (said of the parts themselves). 
trijUgOUS (trij'6-gus or tri-jo'gus), a. [< L. tri- 
jugus, triple-yoked, threefold, < tres (tri-), three, 
+ jugum, yoke.] In bot., same as trijugate. 
+ hora, hour: see hour.'] Happening once in 
every three hours. Lord Ellesmere. (Worcester.) 
adjunct" te hydrograp'htcal, magneticaX 'meteorological', trfjugate (tri-jo'gat), a. [< L. trijugus, three- 
geological, biological, political, anthropological, sociologi- fold (< tres (tri-), three, + jugum, yoke), + 
cal, military, and other surveys. 
trigonometrically (trig"o-no-met'ri-kal-i), adv. 
In a trigonometrical manner ; according to the 
rules or principles of trigonometry. 
An exact Map of all the Province of Attica, trigonomet- 
rically surveyed. 
J. Stua.rta.nd If. Itevett (Ellis's Lit. Letters, p. 883). t^nnction(triljungk'7hon")7" [<."'ire's"(iri-), 
trigonometry (trig-o-nom'e-tri), w. [= F. tri- three, + junctio(n-), junction.] The junction 
gonometrie = Sp. trigonomctria = Pg. It. trigo- of three things. 
nometria, < NL. *trigonometria, < Gr. rpiyuvov, a It is a great convenience to have the trijunction of Tibet, 
triangle, + -fieTpia, < /icrpov, measure.] The India, and Burma focussed within the four corners of a 
mathematical doctrine of the calculation of the 11)a P- Athenxum, Jan. 29, 1887, p. 164. 
angles, sides, and areas of triangles, plane and trilabe (tri'lab), n. [< Gr. rpelf (rpt-), three, + 
spherical, together with that of other quanti- Xa/3'), hold, handle, < "/M^dvuv (]/ ^/3), take.] 
ties intimately related to those. Trigonometry 
embraces also goniometry, or the elementary 
theory of singly periodic functions. 
trigonon (tri-go'non), n. [< Gr. rpiyuvov, a tri- 
angle, a musical instrument so called : see tri- 
;/ol.] Same as trigon 1 , 3 (a). . . - _ 
Female players on the flute, the cithern, and the tri. li s: used in zoology and in botany. 
gonon. C. O. Mailer, Manual of Archaeol. (trans. X 425. tnlammar (tri-lam i-nar), a. [< L. tres (tri-), 
trigonotype (trig'6-no-tlp), . [< Gr. rpiywm,. thr , ee > + '*. Pjate :" see laminar.'] In zool. 
a triangle, + rra-oV, type.] A trigonal trape- and ' tavmg three lamina;, lamell, or lay- 
zohedron. See tetartohedrism. ? rs > three-layered, as a germ that is, consist- 
trigonous (trig'o-nus), a, [< LL. trigo>nts,< Gr. .? of endoderm, mesoderm, and ectoderm. 
rpTyuraf, three-cornered, triangular: see fo-j. trilaminate (tn-lam i-nat), a, [( Ij.jres (tri-), 
j/ow 1 .] 1. Same as trigonal. 2. In bot., three- 
angled; having three prominent longitudinal 
angles, as a stem or an ovary. Also trigonal. 
frM rrfvn n *** /tm. /W\',,vi\ . rMT / T i ,.-' . 
syllable ; also, of or pertaining to what consists 
of three letters. 
Repeating at the same time the triliteral syllable AUM. 
J. F. Clarke, Ten Great Religions, ill. 5. 
Triliteral languages, the Semitic family of tongues : so 
called because their roots in general consist of three con- 
sonants each, which represent the essential idea expressed 
by the word, while special modifications are produced by 
certain vowels or additional letters. 
II. n. A word consisting of three letters. 
triliteralism (tri-lit'e-ral-izm), n. [< triliteral 
+ -ism.'] The use of triliteral roots; the ten- 
dency toward triliterality. 
Triliteralism is so prevalent a law in this family [Semitic 
languages] that sometimes there is a semblance of arti- 
ficial effort to preserve the triliteral form. 
Amer. Jour. Philol., X. 229. 
triliterality (trl-lit-e-rarj-ti), n. [< triliteral 
of consisting of three letters. 
This [Semitic speech] contains two characteristics the 
triliterality of the roots and their inflection by internal 
change. Whitney, Life and Growth of Language, p. 248. 
triliteralness (tri-lit'e-ral-nes), n. Triliter- 
ality. 
trilith (tri'lith), n. [< Gr. rpiWof, of three 
stones, < rpeif (rpi-), three, + AtBof, stone.] A 
monument, or part of a monument, consisting 
of three large stones ; especially, in prehistoric 
A three-pronged surgical instrument for taking 
foreign bodies and small calculi from the blad- 
der. It is so made that the prongs can be moved as de- 
sired after the instrument is in position, 
trilabiate (tri-la'bi-at), a. [< L. tres(tri-), three, 
+ labium, lip.] Three-lipped; having three 
three, + lamina, plate : see laminate.'] 
and bot., consisting of three lamiiuv or layers; 
trilaminar. 
mum (tri-go'num), n. [NL. ^<L. ir&'onum, ^a*? 1 (W-^t'e-ral), a. [< F. trilateral (cf. 
< Gr. rpiyuvov, a triangle : see trigon^.] In anat trt <Mtere), < LL. tnlaterus, three-sided, < L. tres 
a triangular space or area. Specifically- (a) The U n ~)' u 6 ' + . latus (later-), side: see lateral.] 
trigonal space or area at the base of the urinary bladder Having three Sides, 
whose apex is at the beginning of the urethra, and whose trilaterality (tri-lat-e-rari-ti), l. [< trilateral 
+ -ity.~] The character of being trilateral. 
Triangle, [distinguished] from every other class of 
e of the ureters 
n.uin veaieee. (b) 
angles are at the, 
into the bladder: more fully called _ ...._ ,, 
A triangular depressed space between the pulvinar and 
the peduncle of the pineal body : more fully called trigo- 
num iMbenul/e.Trisonvm acustlcl, a triangular area 
on the floor of the f 
cinerea, and inside 
Triliths, Stonchenge, England. 
or inegalithic antiquities, a group consisting 
of two upright stones with a lintel-stone rest- 
ing upon them. Also trilithon. 
mathematical figures by the single character of trilater- trilitMC (tri-lith'ik), a. [< trilith + -ic.~] Of the 
"* Coy, Rhetoric, p. 86. nature of a trilith; consisting of three masses 
teeresWom^ract'Vhelr 11 ' the ^' A trilaterally (tri-lat'e-ral-i), adr. With three of stone. 
form the bM& TrlffOnun babIUli. See dot (61^ sides. trilithon (fri'lith-on), n. [< Gr. rpiWov, neut. 
Trigouum hypoglossl, a triangular area on either side tnlateramesS (tri-lat e-ral-nes), . Trilater- of Tpi/.iSo(, of three stones: see trilith. J Same 
of the middle line of the floor of the fourth ventricle, the ality. as trilith. J. Fergiisson, Hist. Arch., I. 26. 
