Regular tetrahedron (Geom.), a solid bounded by four equal equilateral triangles; one of the five regular solids.
Tet`ra*hex`a*he"dral (?), a. (Crystallog.) Pertaining to a tetrahexahedron.
Tet`ra*hex`a*he"dron (?), n. [Tetra- + hexahedron.] (Crystallog.) A solid in the isometric system, bounded by twenty-four equal triangular faces, four corresponding to each face of the cube.
Tet`ra*kis*hex`a*he"dron (?), n. [Gr. &?; four times + E. hexahedron.] (Crystallog.) A tetrahexahedron.
Tet"ra*ko*sane` (?), n. [Tetra- + Gr. &?; twenty.] (Chem.) A hydrocarbon, C24H50, resembling paraffin, and like it belonging to the marsh-gas series; — so called from having twenty-four atoms of carbon in the molecule.
Te*tral"o*gy (?), n. [Gr. &?;; te`tra- (see Tetra-) + &?; a speech, discourse: cf. F. tétralogie.] (Gr. Drama) A group or series of four dramatic pieces, three tragedies and one satyric, or comic, piece (or sometimes four tragedies), represented consequently on the Attic stage at the Dionysiac festival.
A group or series of three tragedies, exhibited together without a fourth piese, was called a trilogy.
||Te*tram"e*ra (?), n. pl. [NL. See Tetramerous.] (Zoöl.) A division of ||Coleoptera having, apparently, only four tarsal joints, one joint ||being rudimentary. || Te*tram"er*ous (?), a. [Tetra- + Gr. &?; part.] 1. (Bot.) Having the parts arranged in sets of four; as, a tetramerous flower.
2. (Zoöl.) Having four joints in each of the tarsi; — said of certain insects.
Te*tram"e*ter (?), n. [L. tetrametrus, Gr. &?;; te`tra- (see Tetra-) + &?; a measure: cf. F. tétramètre.] (GR. & Latin Pros.) A verse or line consisting of four measures, that is, in iambic, trochaic, and anapestic verse, of eight feet; in other kinds of verse, of four feet.
Tet`ra*meth"yl*ene (?), n. [Tetra- + methylene.] (Chem.) (a) A hypothetical hydrocarbon, C4H8, analogous to trimethylene, and regarded as the base of well-known series or derivatives. (b) Sometimes, an isomeric radical used to designate certain compounds which are really related to butylene.
Tet"ra*morph (?), n. [Tetra- + Gr. &?; form, figure: cf. Gr. &?; fourfold.] (Christian Art) The union of the four attributes of the Evangelists in one figure, which is represented as winged, and standing on winged fiery wheels, the wings being covered with eyes. The representations of it are evidently suggested by the vision of Ezekiel (ch. i.)