[

*n]* - any polyhedron having four plane faces

Found on http://www.webdictionary.co.uk/definition.php?query=tetrahedron

Tet`ra·he'dron noun [ Tetra- + Greek ... seat, base, from ... to sit.] (Geom.) A solid figure inclosed or bounded by four triangles. » In crystallography, the regular tetrahedron is regarded as the hemihedral form of the regular octahedron. Regular tetrahedron (Geom.)

Found on http://www.encyclo.co.uk/webster/T/34

<geometry> A solid figure inclosed or bounded by four triangles. ... In crystallography, the regular tetrahedron is regarded as the hemihedral form of the regular octahedron. ... <geometry> Regular tetrahedron, a solid bounded by four equal equilateral triangles; one of the five regular solids. ... Origin: Tetra- + Gr. Seat, base, fr. T...

Found on http://www.encyclo.co.uk/local/20973

*noun* any polyhedron having four plane faces

Found on https://www.encyclo.co.uk/local/20974

• (n.) A solid figure inclosed or bounded by four triangles.

Found on http://thinkexist.com/dictionary/meaning/tetrahedron/

(from the article `clay mineral`) ...by various scientists including Charles Mauguin, Linus C. Pauling, W.W. Jackson, J. West, and John W. Gruner through the late 1920s to mid-1930s. ... ...lattices of organic compounds and of metals, Fuller developed a vectorial system of geometry that he called `Energetic-Synergetic geometry....

Found on http://www.britannica.com/eb/a-z/t/30

Silicon atom joined by four oxygen atoms (SiO

_{4}). The atomic properties of this molecule cause it to develop a unique three dimensional crystal lattice that is pyramid shaped.

Found on http://www.physicalgeography.net/physgeoglos/t.html

A four-sided polyhedron. A regular tetrahedron, one of the Platonic solids, is a regular three-sided pyramid in which the base-edges and side-edges are of equal length. The projection of a regular tetrahedron can be an equilateral triangle or a square. The centers of the faces of a tetrahedron form ...

Found on http://www.daviddarling.info/encyclopedia/T/tetrahedron.html

tetrahedron: see polyhedron.

Found on http://www.infoplease.com/ce6/sci/A0919479.html

A tetrahedron is a geometric solid figure with four triangular faces.

Found on http://www.probertencyclopaedia.com/browse/AT.HTM

In geometry, a solid figure (polyhedron) with four triangular faces; that is, a pyramid on a triangular base. A regular tetrahedron has equilateral triangles as its faces. The volume (

*V*) of a tetrahedron is given by

*V* = 1/3

*Bh* where ...

Found on http://www.talktalk.co.uk/reference/encyclopaedia/hutchinson/m0006745.html

Ground-based, free-rotating, triangular-shaped wind direction indicator, generally placed near a runway, often lighted at major airports.

Found on http://www.aerofiles.com/glossary.html

In geometry, a tetrahedron (plural: tetrahedra or tetrahedrons) is a polyhedron composed of four triangular faces, three of which meet at each corner or vertex. It has six edges and four vertices. The tetrahedron is the simplest of all the ordinary convex polyhedra and the only one that has fewer than 5 faces. The tetrahedron is the three-dimensio...

Found on http://en.wikipedia.org/wiki/Tetrahedron

1. Four sided polyhedron; all sides are equidimensional and triangular shaped. Minerals shaped as tetrahedrons belong to the isometric system. 2. The building block of all silicates. It is composed of one silicon atom equidimensionally placed around four oxygen atoms. The groups of silicates are classified based on how the tetrahedrons join togeth...

Found on http://www.encyclo.co.uk/local/22291

Ground-based, free-rotating, triangular-shaped wind direction indicator, generally placed near a run

Found on http://www.superglossary.com/Glossary/Technology/Aviation/

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