tetrahedron
NounUS[tet-ruh-hee-druhn]/ˌtɛtrəˈhidrən/4 syllables
Open English WordNet
Noun (1)tetrahedra
- any polyhedron having four plane facesType of polyhedron
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Webster's Dictionary (1913)
Tet′ra·he′dron noun
Origin: Tetra- + Gr. … seat, base, fr. … to sit.
Geometry A solid figure inclosed or bounded by four triangles.
☞ In crystallography, the regular tetrahedron is regarded as the hemihedral form of the regular octahedron.
Regular tetrahedron Geometry, a solid bounded by four equal equilateral triangles; one of the five regular solids.
Webster’s Revised Unabridged Dictionary (1913), from GCIDE 0.54