Icosahedron

In geometry, an icosahedron (/ˌaɪkɒsəˈhiːdrən, -kə-, -koʊ-/ or /aɪˌkɒsəˈhiːdrən/) is a polyhedron with 20 faces. The name comes from Greek εἴκοσι (eíkosi), meaning "twenty", and ἕδρα (hédra), meaning "seat". The plural can be either "icosahedra" (/-drə/) or "icosahedrons".

There are many kinds of icosahedra, with some being more symmetrical than others. The best known is the Platonic, convex regular icosahedron.