What does polyhedral mean?
Polyhedral is an adjective meaning shaped like a polyhedron, which is a three-dimensional solid enclosed by flat faces that meet along straight edges. A cube, a pyramid and a twenty-sided die are all polyhedral objects. The word also covers anything relating to polyhedra, as in polyhedral geometry, which studies their properties. It turns up most often in mathematics, chemistry and crystallography, where it describes the shapes of crystals, molecules and other structures built from flat surfaces. It is also common in hobby settings, especially in the phrase polyhedral dice. The tone is neutral and technical rather than poetic, though it can be used loosely for anything with many flat facets. Polyhedral is a handy word because it names a precise idea in a single term: a solid made of many flat sides, as opposed to a curved form like a sphere or a flat figure like a polygon.
adjectiveHaving the form of a polyhedron, or relating to polyhedra. A polyhedron is a solid figure bounded by many flat faces.
- Having the form of a polyhedron; bounded by many flat faces.
- Relating to polyhedra, as in geometry (for example, polyhedral geometry or a polyhedral angle).
"The crystal grew into a perfect polyhedral shape, its flat faces catching the light at every angle."
"Many tabletop role-playing games use polyhedral dice, whose faces number four, six, eight, ten, twelve or twenty."
"Chemists often describe the shape of a molecule or a crystal as polyhedral when its atoms sit at the corners of a solid with flat faces."
The word 'polyhedral' shares a Greek root with 'cathedral': both build on 'hedra', meaning seat or base.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does polyhedral come from?
Polyhedral is formed in English from polyhedron plus the suffix -al. Polyhedron comes from Greek poly-, meaning 'many', and hedra, meaning 'seat, base or face'. The same Greek hedra appears in tetrahedron and octahedron, and in 'cathedral' through Greek kathedra, 'seat'.
Related word forms
How polyhedral is actually used
Mostly technical or semi-technical, used in mathematics, chemistry, crystallography, architecture and gaming. It is neutral in tone and has no strong connotations.
Easily confused with polyhedral
Polygonal describes a flat, two-dimensional figure with many straight sides, while polyhedral describes a three-dimensional solid with many flat faces.