1. A solid contained by eight equal and equilateral triangles.

Nuttall's Standard dictionary of the English language By Nuttall, P.Austin

• ictahedron,
• kctahedron,
• lctahedron,
• pctahedron,
• 0ctahedron,
• 9ctahedron,
• oxtahedron,
• ovtahedron,
• oftahedron,
• odtahedron,
• otahedron,
• otcahedron,
• octahedorn,
• oktahedron,
• octemeron,
• octameron,
• octaemron,
• Octahedran,
• octahedrit,
• octahedrone

The adjective form of the word "octahedron" is "octahedral".