octahedron
/ˌɑktəˈhidrən/
noun
- A three-dimensional shape with eight flat triangular faces, twelve edges, and six vertices.
- In geometry class, we built a model of an octahedron using straws and string.
- A diamond is sometimes cut into an octahedron to maximize its sparkle.
- The crystal structure of certain minerals naturally forms an octahedron.