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regular icosahedron

regular icosahedron

9.2
A solid with twenty triangles that all have equal sides
  • noun
  • /ˈrɛɡjələr aɪˈkoʊsəˌhɛdrən/
  • Specialized
translation icon : icosaedro regular
  • A regular icosahedron has twenty equilateral triangle faces, making it one of the simplest and most symmetrical geometric shapes.
  • a truncated regular icosahedron

Examples

  • The artist designed a model of a regular icosahedron for her sculpture, using bright colors on each triangular face.

  • In geometry class, we learned that a regular icosahedron can be constructed by connecting points on a sphere.

  • Nothing else fits the bill as well as a truncated regular icosahedron.

    Academic text (1996)
  • All the 60 vertices of a truncated regular icosahedron are identical; each one is the junction of two hexagons and a pentagon.

    Academic text (1996)
  • PHOTO (COLOR): A SOCCER BALL, like a C60 molecule, is essentially a truncated regular icosahedron, with 20 hexagons and 12 pentagons.

    Academic text (1996)

How Many

regular icosahedron
  • Specialized
9.2
regular dodecahedron
  • Specialized
9.6
regular octahedron
  • Specialized
8.4
regular hexahedron
  • Specialized
5.9
regular tetrahedron
  • Specialized
7.4

Surface Forms

Morphology

regular + icosahedron

The phrase is a straightforward adjective + noun composition: 'icosahedron' names a 3D shape with twenty triangular faces and 'regular' specifies symmetry and equal (identical, equilateral) faces. This compositional relation is predictable and follows normal English modifier patterns, so a learner who knows both constituents can derive the MWE meaning.

Etymology

Regular icosahedron names a 3D shape made of twenty equal 'faces' that are triangles, where regular means every part is the same and icosahedron points to the twenty sides. Imagine a ball built from twenty identical triangle panels, and that image explains why the term means a solid with twenty identical triangle faces.