- Geometry. a solid contained by four plane faces; a triangular pyramid.
- any of various objects resembling a tetrahedron in the distribution of its faces or apexes.
Origin of tetrahedron
Examples from the Web for tetrahedron
A scalene triangle abc might also be employed, or a tetrahedron.
The Tetrahedron, having four equilateral triangles as faces.Bygone Beliefs
H. Stanley Redgrove
Its head was a pyramid, a tetrahedron; its length vanished in the further darkness.The Metal Monster
It occurs crystallized in the form of the tetrahedron, also massive and disseminated.The New Gresham Encyclopedia
Round Mars describe a tetrahedron; the sphere including this will be Jupiter.Kepler
Walter W. Bryant
- a solid figure having four plane faces. A regular tetrahedron has faces that are equilateral trianglesSee also polyhedron
- any object shaped like a tetrahedron
Word Origin and History for tetrahedron
solid figure contained by four triangular surfaces, 1560s, from Late Greek tetraedron, originally neuter of tetraedros (adj.) "four-sided," from tetra- "four" + hedra "seat, base, chair, face of a geometric solid," from PIE root *sed- (1) "to sit" (see sedentary).
- A polyhedron having four faces.