tetrahedron
[te-truh-hee-druh n]
- 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.
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Origin of tetrahedron
Dictionary.com Unabridged
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for tetrahedra
Historical Examples
The atoms are arranged in two tetrahedra with a common apex, and the relationship is maintained in the meta-body, a septet.
Occult ChemistryAnnie Besant and Charles W. Leadbeater
The globe, e, is a new form, the four tetrahedra of the proto level making a single twelve-atomed one on the meta.
Occult ChemistryAnnie Besant and Charles W. Leadbeater
The smallest particles of fire are tetrahedra, of air octahedra, of water icosahedra.
A Critical History of Greek PhilosophyW. T. Stace
tetrahedron
- a solid figure having four plane faces. A regular tetrahedron has faces that are equilateral trianglesSee also polyhedron
- any object shaped like a tetrahedron
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Word Origin
C16: from New Latin, from Late Greek tetraedron; see tetra-, -hedron
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
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Word Origin and History for tetrahedra
tetrahedron
n.
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).
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Online Etymology Dictionary, © 2010 Douglas Harper
tetrahedron
[tĕt′rə-hē′drən]
- A polyhedron having four faces.
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The American Heritage® Science Dictionary
Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.