n. (pl. octahedrons or octahedra)
1. a solid figure contained by eight (esp. triangular) plane faces.
2 a body, esp. a crystal, in the form of a regular octahedron.
Phrases and idioms:
regular octahedron an octahedron contained by equal and equilateral triangles.
Derivatives:
octahedral adj.
Etymology: Gk oktaedron (as OCTA-, -HEDRON)