'Regular icosahedron' definitions:

Definition of 'regular icosahedron'

(from WordNet)
noun
An icosahedron with twenty equilateral triangles as faces

Definition of 'Regular icosahedron'

From: GCIDE
  • Icosahedron \I`co*sa*he"dron\, n. [Gr. ?; ? twenty + ? seat, base, fr. ? to sit.] (Geom.) A solid bounded by twenty sides or faces. [1913 Webster]
  • Regular icosahedron, one of the five regular polyhedrons, bounded by twenty equilateral triangules. Five triangles meet to form each solid angle of the polyhedron. [1913 Webster]