Wiktionary
n. (context geometry English): An Archimedean solid with 20 regular triangular faces, 30 regular square faces, 12 regular pentagonal faces, 60 vertex and 120 edges.
Wikipedia
In geometry, the rhombicosidodecahedron, or small rhombicosidodecahedron, is an Archimedean solid, one of thirteen convex isogonal nonprismatic solids constructed of two or more types of regular polygon faces.
It has 20 regular triangular faces, 30 square faces, 12 regular pentagonal faces, 60 vertices and 120 edges.
The name rhombicosidodecahedron refers to the fact that the 30 square faces lie in the same planes as the 30 faces of the rhombic triacontahedron which is dual to the icosidodecahedron.
It can also be called an expanded or cantellated dodecahedron or icosahedron, from truncation operations on either uniform polyhedron.