[1] : The Collaborative International Dictionary of English v.0.48

octahedron \oc`tahe"dron\ o^k`t.ah=e"dro^n, n. gr.
   'okta`edron, fr. 'okta`edros eight-sided; 'okta- for 'oktw`
   eight + "e`dra seat, base, from "e`zesqai to sit. geom.
   a solid bounded by eight faces. the regular octahedron is
   contained by eight equal equilateral triangles.
   1913 webster

[2] : WordNet (r) 2.0

octahedron
     n : any polyhedron having eight plane faces
     also: octahedra pl
see also:
octahedra 

Octahedron >> O Words
Octahedron, definition of term: Octahedron
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