Definition of "tetrahedron" [tet•ra•he•dron]

• A polyhedron with four faces. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "A tetrahedron is a good model for e.g. a carbon atom in a molecular form, and the tighter the "packing," the tighter the molecular bonds."
• "Otherwise known as a tetrahedron, a "Caltrop", or to a lesser degree "Ol' Pointy"."
• "Your tetrahedron could be our key to all the mysteries of Omegan science and history."