Definitions
American Heritage® Dictionary of the English Language, Fourth Edition
- n. A polyhedron with four faces.
Century Dictionary and Cyclopedia
- n. A solid comprehended under four plane faces; especially, the regular tetrahedron, or triangular pyramid having its base and sides equilateral triangles. In crystallography and in geometry the tetrahedron is regarded as a hemihedral form of the octahedron, four of whose faces form the plus, and the four alternate faces (two above and two below) the minus tetrahedron. The figures represent the tetrahedron in the position required to exhibit its relation to the octahedron. See
hemihedral .
Wiktionary
- n. geometry a polyhedron with four faces; the regular tetrahedron, the faces of which are equal equilateral triangles, is one of the Platonic solids.
GNU Webster's 1913
- n. (Geom.) A solid figure inclosed or bounded by four triangles.
WordNet 3.0
- n. any polyhedron having four plane faces
Etymologies
- From Ancient Greek τετράεδρον (tetraedron, "triangle-based pyramid"), from τετράς (tetras, "four") + ἕδρα (hedra, "seat"). (Wiktionary)
- Late Greek tetraedron, from Greek, neuter of tetraedros, four-faced : tetra-, tetra- + hedrā, face of a geometric solid. (American Heritage® Dictionary of the English Language, Fourth Edition)
Examples
“A tetrahedron is a good model for e.g. a carbon atom in a molecular form, and the tighter the "packing," the tighter the molecular bonds.”
“Otherwise known as a tetrahedron, a "Caltrop", or to a lesser degree "Ol' Pointy".”
“Your tetrahedron could be our key to all the mysteries of Omegan science and history.”
“In our space, four equidistant points can be located, the vertices of a tetrahedron, that is, a pyramid having four triangular faces.”
“It will be seen that the tetrahedron is the fundamental form, the three-sided pyramid on a triangular base, _i. e._, a solid figure formed from four triangles.”
Occult Chemistry Clairvoyant Observations on the Chemical Elements
“The tetrahedron is the form of chromium and molybdenum, but not that of the head of their group, oxygen, which is, like hydrogen, _sui generis_.”
Occult Chemistry Clairvoyant Observations on the Chemical Elements
“Above the tetrahedron is a balloon-shaped figure, apparently drawn into shape by the attraction of the tetrahedron.”
Occult Chemistry Clairvoyant Observations on the Chemical Elements
“A classic 3D fractal is the Sierpinski tetrahedron, which is a tetrahedron of tetrahedra of tetrahedra, etc.”
“Through them, one had a spec - tacular view across the river to the futuristic Flamme d'Or, the Phillippe Starke-designed building of black glass, a kind of tetrahedron on acid, surmounted by a vaguely flamelike shape derisively christened by Tokyoites "the Golden Turd.”
“For the first prize in 1901 the Academy had to consider 20 nominations, but no less than 11 of these named van't Hoff, who was also chosen by the Committee for Chemistry. van't Hoff had already during his thesis work in Utrecht in 1874 published his suggestion that the carbon atom has its four valences directed towards the corners of a regular tetrahedron, a concept which is the very foundation of modern organic chemistry.”
The Nobel Prize in Chemistry: The Development of Modern Chemistry
Lists
These user-created lists contain the word ‘tetrahedron’.
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Very Silly Words
A list of very silly sounding words, as well as words that are fun to say
badot, gardyloo, dingbat, gaffer, kine, haberdashery, forsooth, whey-faced, hoddypeak, brouhaha, widdershins, decemnovenarianize and 115 more...
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My Little Phonies
Names for the next generation of My Little Ponies. Inspired by Star's list.
juggernaught, flamboyant, cuddly maggot, astrobleme, agroof, windburn, poshlost, crucifer, feedbag, dunderwhelp, nebelwerfer, bliss ninny and 453 more...
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JimboBaggins's list
paraphenalia
haberdashery, desideratum, esoteric, retribution, retrograde, tetrahedron, iridescent, tentative, siphon, soothsayer, wanderlust, patina and 16 more...
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tetra-
four, having four
tetraploidy, tetragram, tetrahedron, tetragamy, tetradactyly
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Great Race Horse Names10
poetry in motion - words at work.
illuminator, bonk, testify to love, passion for gumbo, grimacing, above a whisper, jazz ensemble, dinner in the diner, marginal reality, scalding passion, you wont like it, umber and 216 more...
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Time for a new list!
abrupt, erupt, rupture, sync, appropinquity, heterochromia, homochromatic, monochromatic, willy nilly, nitty gritty, kowtow, wonton and 455 more...
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Words of Whimsy & Grace
abecedary, addendum, ampersand, anachronism, avuncular, balderdash, barnacle, befuddle, behemoth, bejeebers, blabbermouth, blatherskite and 465 more...
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Jigsaw Codex
List? What list?
This is the list that makes up the world.cat, boustrophedon, syndetic, life, imbroglio, interlude, composition, investigation, cantankerous, him, sign, universality and 189 more...
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Just 'cause I like 'em, T
torquate, thalassocracy, toothsome, travois, tempestuous, tone, tincture, tripwire, tether, trill, tenacious, travesty and 355 more...
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Regular polyhedra
This class consists of the five Platonic solids, (the only regular convex polyhedra), and the four Kepler-Poinsot (regular starry) polyhedra.
polyhedron, platonic solid, cube, octahedron, hexahedron, tetrahedron, dodecahedron, icosahedron, dual polyhedra, symmetry groups, schläfli symbol, face and 18 more...
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multi-dimensional geometric tessellat...
( _mark, personal list, patterns, randomness )
related:
http://www.wordnik.com/lists/hedrons
more:
node, polytope, polygon, polyxennon, polyyotton, polyzetton, polyexon, polypeton, polyteron, polychoron, polyhedron, cubicuboctahedron and 31 more... -
geometry
catenary, angle, ray, segment, sector, circle, chord, diameter, radius, area, perimeter, volume and 49 more...
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Nifty Math Words
A list of nifty or "cool" math words
parabola, isosceles, matrix, oblique, reciprocal, algorithm, asymptote, ellipsis, hypercube, infinitesimul, isometry, jerk and 8 more...
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mcbaine's Words
surficant, vicissitude, erinaceous, battousai, himura, wang, pedagogical, pedantic, immure, tertiary, tetrahedron, widget and 104 more...
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whurds
elongate, niche, methamphetamine, amphetamine, parallel, barn, zenzizenzizenzic, troubadour, cavalcade, baroque, passages, signal and 36 more...
Tweets
Looking for tweets for tetrahedron.

sionnach Uri Geller gushes: "I haven't needed to buy a single razor blade since I discovered the healing aura of the tetrahedron right here in Area 51"
Uri touts the power of tetrahedrically enhanced razor blades
But I agree with seanahan, among the five Platonic solids, the dodecahedron and icosahedron are cooler.
If the pointiness becomes an issue, there is always the class of Johnson solids to consider. I don't know exactly what a gyroelongated pentagonal cupolarotunda (J47) looks like*, but I'd certainly make room for one right next to my metabidiminished rhombicosidodecahedron (J81) and my snub square antiprism (J85).
* OK, here's a picture: J47.gif Jan 19, 2009
rolig I wonder if Classifiedinformation is thinking of the special energy some new-age mysticists associate with pyramids. Jan 19, 2009
seanahan What? The coolest? The dodecahedron and icosahedron are way cooler. Jan 19, 2009
kewpid It is a pretty neat shape. But don't you find it a little pointy? Jan 18, 2009
classifiedinformation A polyhedron with four triangular sides.
Also known as the coolest shape in the world. Jan 18, 2009