octahedron
Polyhedron, eight triangles
An octahedron is a three-dimensional shape with eight flat faces.
The regular octahedron—the form usually meant—has eight equilateral triangles as faces, like two square-based pyramids joined at their bases.
It appears in chemistry to describe molecular geometry and is one of the five Platonic solids.
Plural: octahedra or octahedrons.
Six-squared-faced solid
- polyhedraMulti-faced geometric solids
- regularOccurring at fixed intervals
- convexCurved outward externally
- ArchimedeanOf a Syracusan polymath
Euclidean · classical · elemental · ideal · perfect · uniform · deltahedron · dual
Corner points of shapes
- edgesOuter limits or boundaries
- facesFront of heads
- three-dimensionalHaving volume and depth
- convexCurved outward externally
regular · vertex · angle · dihedral · volume · surface · area · trigonometry
Calcium-based cubic mineral
- diamondCrystallized carbon gemstone
- spinelOxide mineral, octahedral crystals
- pyriteBrass-yellow iron sulfide
- magnetiteMagnetic iron ore
habit · lattice · twinning · cleavage · formation · mineralogy · crystallography · atomic
Greek philosopher, academy founder
- elementBasic substance or factor
- airGaseous envelope surrounding Earth
- philosophyStudy of fundamental truths
- classicalOf ancient Greece/Rome
ancient · ideal · form · sacred · esoteric · mystical · cosmology · harmony
Turning on an axis
- reflectionReturned light or thought
- axisRotation reference line
- isometryDistance-preserving map
- invarianceQuality of staying unchanged
fourfold · threefold · inversion · rotational · chiral · achiral · symmetric
cube
Six-squared-faced solid
- polyhedraMulti-faced geometric solids
- regularOccurring at fixed intervals
- convexCurved outward externally
Archimedean · Euclidean · classical · elemental · ideal · perfect · uniform · deltahedron · dual · stellated
vertices
Corner points of shapes
- edgesOuter limits or boundaries
- facesFront of heads
- three-dimensionalHaving volume and depth
convex · regular · vertex · angle · dihedral · volume · surface · area · trigonometry · mathematics
fluorite
Calcium-based cubic mineral
- diamondCrystallized carbon gemstone
- spinelOxide mineral, octahedral crystals
- pyriteBrass-yellow iron sulfide
magnetite · habit · lattice · twinning · cleavage · formation · mineralogy · crystallography · atomic · structure
Plato
Greek philosopher, academy founder
- elementBasic substance or factor
- airGaseous envelope surrounding Earth
- philosophyStudy of fundamental truths
classical · ancient · ideal · form · sacred · esoteric · mystical · cosmology · harmony · proportion
rotation
Turning on an axis
- reflectionReturned light or thought
- axisRotation reference line
- isometryDistance-preserving map
invariance · fourfold · threefold · inversion · rotational · chiral · achiral · symmetric
- 3D shapescube, sphere, cone, cylinder, pyramid
- geometric shapessphere, triangle, square, cone, rectangle
- shapescircle, square, triangle, rectangle, oval
- 3D Geometrycube, sphere, cone, cylinder, pyramid
- eight prefixoctave, October, octuple, octuplet, octillion
- Greek mathematicsEuclid, Archimedes, Pythagoras, geometry, theorem
octahedroncube
Six-squared-faced solid
hexahedron · tetrahedron · icosahedron · sphere · dodecahedron