Tet·ra·he·dron n. Geom. A solid figure inclosed or bounded by four triangles.
Note: ☞ In crystallography, the regular tetrahedron is regarded as the hemihedral form of the regular octahedron.
Regular tetrahedron Geom., a solid bounded by four equal equilateral triangles; one of the five regular solids.
◄ ►
regular tetrahedron
n : a tetrahedron with four equilateral triangular faces