What does dodecahedron mean?
A dodecahedron is a three-dimensional solid with twelve flat faces, making it one of the classical figures of geometry. In its most celebrated form — the regular dodecahedron — all twelve faces are identical regular pentagons joined at equal angles, one of the five Platonic solids revered since ancient Greece. The word appears chiefly in mathematical and scientific contexts: geometers study its symmetry, mineralogists encounter dodecahedral crystal forms, and tabletop gamers roll twelve-sided dice shaped like it. Because it names a precise technical object, the term carries a scholarly, exacting connotation rather than any emotional coloring. Its Greek-derived name transparently signals its structure, combining 'dodeka' (twelve) with 'hedra' (seat or face), so the word effectively explains itself to anyone familiar with classical roots. Familiarity with dodecahedron also unlocks a family of related terms — tetrahedron, octahedron, icosahedron — that together describe the fundamental building blocks of three-dimensional space, making it a rewarding word for anyone interested in the language of shapes.
nounA three-dimensional solid figure with twelve flat faces, each of which is a regular pentagon in the regular dodecahedron.
- A solid geometric figure with twelve plane faces; in its regular form, all twelve faces are identical regular pentagons.
"The children built a dodecahedron from cardstock as part of their geometry project."
"A standard twelve-sided die used in role-playing games takes the form of a regular dodecahedron."
"Some theories in cosmology propose that the universe might have the overall shape of a dodecahedron."
'Dodecahedrons' is the ordinary plural in general use; the Latinate 'dodecahedra' is common in academic and mathematical writing. Both are correct.
"The classroom set included several cardboard dodecahedra alongside cubes and pyramids."
The regular dodecahedron was Plato's symbol for the cosmos itself — he reserved this twelve-faced wonder for the heavens after assigning the other four elements to simpler solids.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of dodecahedron
Dodecahedron comes from Greek 'dōdekáedron', formed from 'dōdeka' (twelve) and 'hedra' (face or seat), the same root that gives '-hedron' endings to tetrahedron, octahedron, and icosahedron. The term entered English in the late sixteenth or early seventeenth century, transmitted through Latin scholarly writing on geometry during the Renaissance revival of Euclid and the Greek mathematicians. Its cognates include dodecagon, which shares the 'twelve' root but describes a two-dimensional figure, and the broader family of polyhedron names derived from 'hedra'.
How dodecahedron is actually used
Dodecahedron belongs to formal, technical registers — mathematics, geometry, crystallography, and gaming — and would sound out of place in everyday conversation. The plural 'dodecahedrons' is fully standard, though 'dodecahedra' appears in academic writing. It most often occurs with modifiers such as 'regular' or in discussions of Platonic solids, dice, and crystal forms.
Easily confused with dodecahedron
An icosahedron has twenty triangular faces, whereas a dodecahedron has twelve pentagonal faces.
A dodecagon is a two-dimensional shape with twelve sides, while a dodecahedron is a three-dimensional solid with twelve faces.