TET
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TETANOS, in Medicine, a Term purely Greek, and fignifying a kind of Tonic Spaimus, or Convulfion, where- in the fore and hind Mufcles of the Head are render'd rigid and inflexible ; ib that it can neither bend one Way nor t'other. See Convulsion.
The Word is form'd from the Greek, iitm?. to ftrerch.
Some Authors alio ufe Tetany! , or Tetanus in a more ge- neral Senie. When a Convulfion is umverial, they denomi- nate it 'Tetanus i which they fub-divide into Emprojl hot onus and Opifihctonus, See Emprosthotonos and Ei'isthoto- nos.
TETRACHORD, in the ancient Mufic, a Concord con- fitting of three Degrees, Tones, or Intervals, or four Sounds or Terms 5 call'd alio by the Ancients fiiamtfty, and by the Moderns a Fourth. See Fourth.
This Interval had the Name Tetrachord given it with refpecT: to the Lyra, and its Chords or Strings. See Chord.
Sec alio DlATESSARON.
Ancient Authors make frequent Mention of the Synaphe, or Conjunction 5 and Diefcufis, or Disjunction of Tetra- chords. To conceive their Meaning, it muft be oblerv'd, that two Tetrachords were faid to be join'd, when the fame Chord was the higheft of the firit, or low eft Inftrument, and the loweft of the lecond 5 as was the Cafe in the two Tetrachords that compote the ancient Heptachord or Seventh. But when two "Tetrachords had no common Chord 5 but, on the contrary, had each their different ones to begin and end withal, fo that between the two there were two Intervals of a Tone, then the Tetrachords were faid to be disjoin'd 5 ■which was the Cafe in the two Tetrachords that compote the Octachord or Oiiave. See Octave.
The Word is form'd of the Greek, -m§ct, four times, and XpgJto, a Chord or String.
TETRACTYS, in the ancient Geometry. The Tytha- goric Tetratlys is a Point, a Line, a Surface, and a Solid.
TETRADIAPASON,a e ^wYr^/ff©^>;; a Mufical Chord, otherwiic call'd a quadruple eight or nine and twen- tieth. See Diapason.
TETRADITES, in Antiquity, a Name given to feveral different Se&s of Hereticks, out of ibme particular Refpecl ■ they bore to the Number year, tvt&l-
The Sabbathians were call'd Tetradites, from their failing on JBafter-T)ay, as on the fourth Day, or Wednefday. See Sabbathian.
The Manichees, and others, who admitted a Quatemity inftead of a Trinity in the Godhead, or four Periuns in lieu of three, were alio call'd Tetradites. SccManichee.
The Followers of Spstms Fullenjis bore the fame Appella- tion of Tetradites, by Reafon of the Addition they made to the Trijagwn, to countenance an Error they held, that in our Saviour's Paffion, 'twas not any particular Perion of the Godhead, e.gr. the Son, that iuffer'd ; but the whole Deity. See Trisagioni
The Ancients alio gave the Name Tetradites to Children born under the fourth Moon ; and theie they believ'd un- happy.
The Word is form'd from the Greek, ykfl&fas or TsWafSf, four.
TETRAEDRON, Tetrahedron, in Geometry, one of the five regular or Platonic Bodies, or Solids 5 com- prehended under four equilateral and equal Triangles. See Solid.
The Tetraedron may be conceiv'd as a triangular Pyramid of four equal Faces. See Pyramid.
Such is that reprefented (Tab. Geometry, Fig, 59.) See Regular Body.
'Tis demonttrated by Mathematicians, that the Square of the Side of a Tetraedron, is to the Square of the Diameter of a Sphere wherein it may be inicrib'd, in a fubfefquialteral Ratio : Whence it follows, that the Side of a Tetraedron is to the Diameter of a Sphere it is inferib'd in, as 1/2 to the y^, confequently they are incommenfurable.
TETRAGON, in Geometry, a Quadrangle j or a Figure with four Angles. See Quadrangle.
Thus a Square, Parallelogram, Rhombus, Trapezium, are Tetragonal Figures, See Square, &c.
"The Word is form'd from the Greeks Ts'mfif, four, and yoyiA, Angle.
Tetragon, in Aftrology, &c, anAfpe&of two Planets with Regard to the Earth, when rhey are diflant from each other a fourth Part of a Circle, or 90 3 as AD Tab. Agro- nomy, Fig. 3.
The Tetragon is exprefs'd by the Character, □. See Aspect.
TETRAGONIAS, a Name given to a Comet, whofe Head is of a Quadrangular Figure, and its Tail or Train long, thick, and uniform ; not much different from the Me- teor call'd Trabs. See Comet and Trabs.
TETRAGONISM, a Term lbme Authors ufe to exprefs the Quadrature of the Circle. See Quadrature.
TETRAGONUS, in Anatomy, a Mufcle, call'd alfo /■^a.-iraws Gen<c. See Quadratus
TETRAGRAMMATON, a Denomination P iven by the Greeks to the Name of God, becaufe confuting of four Let- ters in moll Languages. Sec God.
TETRAMETER, in the ancient Poetry, an Iambic Verfe confining of eight Feer. See Iambic.
We meet with none of theie but in the Comic Poets, a? Terence.
The Word is form'd from the Greek, Tr'-w^z, four, and fw]£«p; Meafure, q. d. four Mea lures.
TETRAPASTUS, in Mechanicks, a Machine wherein are four Pullies. See Pully.
The Word is form'd from the Greek, r ni^.m.?r i \\ See Polypastus.
TETRAfETALOUS, in Botany, an Epithet given to Flowers that confift of four 'Petala, or Leaves, plac'd a- round the Piitil. SeePxVAtA.
Theie, M. JuJJim calls Tolypetalous Flowers. See Poly-
PETALOUS.
_Mr. Ray, who calls them Tretapetalous, makes them con- ithute a diltinct Kind, which he divides into
i Q . Such as have an uniform Tetrapetalous Flower, and their Seed-VeMels a little oblongifh, which he therefore calls Siliquofe ; as the Keiri or Leucoium Luteum, and the other common Leucoium, the Dentaria, the Leucoium Siliquo- fum, AlyiTon, Viola Lunaris, Paronychia, Hefperis, Allia- ria, Rapa, Napus, Sinapis, Rapiltoim, Eruca Spuria, Eri- fimum, Cardan-iine, Turritis, Pilolella Siliquola, and the Raphanus RuOicanus and Aquaticus.
2°. Such as have their Seed Cafe or VelTel fiiorter, which therefore, for Diftinclion Sake, he calls Capfu/attc, and Silt- cutoff 5 as the Myagrum, Draha, Leucoium Siliqua iubro- tunda, Cochlean'a, Nafturtium, Lepidium vulgare, Thlafpi, Brafica marina, Glaftum, Eruca marina, &c.
3. Such as have afeeming Tetrapeta/bus Flower, that is, a Monopetalous one, divided deeply into four Partitions ; which he particularly calls Anomalous - y as the Papaver, Agremony, Veronica, Titbymallus, Plantago, Cnronopus, Piyilium, Lyfi- machia Siliquola, Alfine fburia, ££>c.
TETRAPHARMACUM, from t^t^ quater, four, and <pat[/J.y.ov, Medicamentum, is any Remedy confuting of four Ingredients.
TETRAPLA, in Church Hiftory, a Bible difpos'd by Origen under four Columns, in each whereof was a different Greek Verfion, viz. that of Aquila 7 that of Sy?nmachus t that of the Seventy, and that of Theodofian. See Bible.
Sixtus of Sienna confounds the Tetrapla with the Hexa- pla; but the Te:?-apla is a different Work, compos'd after the Hexapla, in Favour of fuch as could not have the Hexa- fila. See Hexapea;
Some Authors are of Opinion, that the Order wherein the four Verlions of the Tetrapla were rang'd, was different from that wherein we have rehears'd them j and particularly that the Septuagint was in the firft Column : But S. Bpi- phanius fays exprefsly to the contrary, and places it in the third. He even gives us Origen* Reafon for putting it there ; which was, lays he, that the belt Verfion might be in the Middle, that the others might be the more ealily confronted therewith, and corrected from it,
Baronius, however, in his Annals for the Year 231, takes the Septuagint to have been in the third Place in the Hex a- fla, but the firft in the TetraJ>la$ yet Fftiphanius gives it the lame Place in both.
The Word is form'd from the Greek 7ST££;rAo£V, quadru- plex, four r old.
TETRAFTOTE, Tetraptoton, in Grammar, fuch defective Nouns as have only four Cafes 5 as This, which wants the Dative and Vocative fingular. See Case, Ae-
TOTE, £$C.
TETRARCH, Tetrarcha, a Prince who holds and governs a fourth Part ot a Kingdom ; thus call'd from the Greekii-m&s, fourth, andet^ti, Rule, Dominion.
Such, originally, was the import of the Title Tetrarch ; but it was afterwards apply'd to any petty King, or Sove- reign, and became iynonymous with Etbnarch ; as appears from the following Confederation ; i°. That ^Pliny makes mention of fix Tetrarchies within the Cities of 1)ecafolis. 2 Q - That Herod's Kingdom was only divided into three Parts, which yet were call'd Tetrarchies, and the Sovereigns thereof, Luke iii. \. T'etrarchs. 3 . Jo[ephus, Antiq. Jud. lib. xiv. c. 23. tells us, that after the Battle of 'Fhilipp'^ Anthony going into Syria, conttituted Herod, Tetrarch ; and on Medals the fame Herod is call'd Ethnarch. See Eth-
NARCHA.
TETRASTICH, a Stanza, Epigram, or Poem, confift- ing of four Verfes. See Distich.
'TETRASTYLE, in the ancient A chiteaure, a Build- ing, and particularly a Temple, with four Columns both before and behind, /. e. in Front and Rear. See Tem- ple.
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