Rhombohedra

Part of speech: noun

Definitions

1. A three-dimensional geometrical shape with six faces, each of which is a rhombus, presenting a symmetrical structure
2. An asymmetric polyhedron defined by parallelogram faces, often found in crystallography and geometric studies
3. A solid figure categorized as a type of polyhedron, characterized by its distinctive rhombic shape and unique spatial properties

Etymology: "Rhombohedra" is the plural of "rhombohedron", a solid bounded by six rhombus-shaped faces. The singular is a compound of two Greek-derived pieces: "rhombo-", from "rhombos" (a spinning top, or a rhombus-shaped figure), and "-hedron", from Greek "hedra" meaning seat or base, the same root that gives "cathedral" its sense of a seat of authority. Put together, the name describes a solid with rhombic faces standing as its bases. The first element carries a surprise. The Greek "rhombos" originally referred to something that spins or whirls, such as a bullroarer or a spinning top, and only later came to name the flat, slanted quadrilateral we call a rhombus. The shape was named for the motion of the toy rather than the other way around.