(ためんたい)

ためんたい
noun
polyhedron
1. polyhedron (geometry)
A three-dimensional solid whose surface consists of flat polygonal faces joined at straight edges and sharp corners (vertices). A standard term from geometry.
(せい)多面体(ためんたい)(いつ)つある。
There are five regular polyhedra.
サイコロは立方体(りっぽうたい)という多面体(ためんたい)だ。
A die is a polyhedron called a cube.
この問題(もんだい)では、多面体(ためんたい)表面積(ひょうめんせき)計算(けいさん)する。
In this problem, we calculate the surface area of a polyhedron.
美術館(びじゅつかん)中央(ちゅうおう)には、ガラスでできた巨大(きょだい)多面体(ためんたい)彫刻(ちょうこく)()かれていた。
In the center of the museum stood a huge polyhedron sculpture made of glass.

Composed of () (many) + (めん) (face, surface) + (たい) (body, solid) — literally "many-faced solid." A technical term from geometry that refers to any solid with flat polygonal faces.

COMMON COLLOCATIONS:

  • (せい)多面体(ためんたい): regular polyhedron (Platonic solid)
  • 多面体(ためんたい)頂点(ちょうてん): vertex of a polyhedron
  • 多面体(ためんたい)(へん): edge of a polyhedron
  • 多面体(ためんたい)(めん): face of a polyhedron
  • 多面体(ためんたい)体積(たいせき): volume of a polyhedron

RELATED TERMS:

  • 立方体(りっぽうたい): cube — a regular polyhedron with six square faces
  • 四面体(しめんたい): tetrahedron — a polyhedron with four triangular faces
  • 八面体(はちめんたい): octahedron — a polyhedron with eight faces
  • 十二面体(じゅうにめんたい): dodecahedron — a polyhedron with twelve faces
  • 二十面体(にじゅうめんたい): icosahedron — a polyhedron with twenty faces

USAGE:
The word is used in classrooms, textbooks, and technical writing about mathematics, crystallography, and computer graphics. In casual descriptions of shapes, Japanese speakers more often refer to the specific shape (e.g., サイコロ(さいころ)(がた), cube-shaped) rather than using the umbrella word 多面体(ためんたい).