A polyhedron is a three-dimensional geometric figure whose sides are comprised of flat polygonal surfaces (faces). The faces meet in edges which are straight-line segments, and the edges meet in points called vertices. Polyhedrons are named after the number of faces.
In 2376, Icheb created a 26-sided polyhedron out of clay, composed of hexagons, octagons and squares. Seven of Nine was impressed by Icheb's work. (VOY: "Ashes to Ashes")