Tetrahedron

• POS: Noun
• HYPHEN: tet=ra=he=dron

CIDE DICTIONARY

Tetrahedron, n. [Tetra- + Gr. seat, base, fr. to sit.].

 A solid figure inclosed or bounded by four triangles.  [1913 Webster]
" In crystallography, the regular tetrahedron is regarded as the hemihedral form of the regular octahedron."  [1913 Webster]

Regular tetrahedron (Geom.), a solid bounded by four equal equilateral triangles; one of the five regular solids.

OXFORD DICTIONARY

Tetrahedron, n. (pl. tetrahedra or tetrahedrons) a four-sided solid; a triangular pyramid.

Derivative

tetrahedral adj.

Etymology

late Gk tetraedron neut. of tetraedros four-sided (as TETRA-, -HEDRON)

ROGET THESAURUS

Tetrahedron

Four

N quaternity, four, tetrad, quartet, quaternion, square, quarter, tetract, tetragon, quadrangle, rectangle, tetrahedron, quadrature, quadrifoil, quadriform, quadruplet, quatrefoil, tetrapod, quadrangle, quad, quadrupole, quadrivium, four, quaternary, quaternal, quadratic, quartile, tetract, tetractic, tetractinal, tetrad, tetragonal, square, quadrate.

Angularity

N angularity, angularness, aduncity, angle, cusp, bend, fold, notch, fork, bifurcation, elbow, knee, knuckle, ankle, groin, crotch, crutch, crane, fluke, scythe, sickle, zigzag, kimbo, akimbo, corner, nook, recess, niche, oriel, coign, right angle, obliquity, angle of 45 degrees, miter, acute angle, obtuse angle, salient angle, reentering angle, spherical angle, angular measurement, angular elevation, angular distance, angular velocity, trigonometry, goniometry, altimetry, clinometer, graphometer, goniometer, theodolite, sextant, quadrant, dichotomy, triangle, trigon, wedge, rectangle, square, lozenge, diamond, rhomb, rhombus, quadrangle, quadrilateral, parallelogram, quadrature, polygon, pentagon, hexagon, heptagon, octagon, oxygon, decagon, pyramid, cone, Platonic bodies, cube, rhomboid, tetrahedron, pentahedron, hexahedron, octahedron, dodecahedron, icosahedron, eicosahedron, prism, pyramid, parallelopiped, curb roof, gambrel roof, mansard roof, angular, bent, crooked, aduncous, uncinated, aquiline, jagged, serrated, falciform, falcated, furcated, forked, bifurcate, zigzag, furcular, hooked, dovetailed, knock kneed, crinkled, akimbo, kimbo, geniculated, oblique, fusiform, wedge-shaped, cuneiform, cuneate, multangular, oxygonal, triangular, trigonal, trilateral, quadrangular, quadrilateral, foursquare, rectangular, square, multilateral, polygonal, cubical, rhomboid, rhomboidal, pyramidal.