icosahedron

== English == === Alternative forms === eicosaedrum (obsolete) icosaedrum (obsolete) === Etymology === From Ancient Greek εἰκοσάεδρον (eikosáedron), from εἴκοσι (eíkosi, “twenty”) + ἕδρα (hédra, “face of a geometrical solid”). Equivalent to icosa- +‎ -hedron. === Pronunciation === IPA(key): /ˌaɪkoʊsəˈhiːdɹən/, /ˌaɪkɒsəˈhiːdɹən/, /ˌaɪkɔsəˈhiːdɹən/ === Noun === icosahedron (plural icosahedra or icosahedrons) (geometry) A polyhedron with twenty faces. (geometry, specifically) A regular icosahedron: one of the Platonic solids, all of whose faces are regular (equilateral) triangles Synonym: regular gyroelongated pentagonal bipyramid ==== Derived terms ==== ==== Related terms ==== icosahedral icosahedrite ==== Translations ====