Not all groups of eubacteria have peptidoglycan, so all eubacteria may be classified as either Gram-positive (able to bind Gram's stain) or Gram-negative (unable to bind Gram's stain).
A portable DVD player is in the shape of a rectangular prism. A soccer ball is in the shape of a truncated icosahedron. These shapes are all examples of polyhedra. A three-dimensional shape whose faces are polygons is known as a polyhedron. This term comes from the Greek words poly, which means many, and hedron, which means face.. So, quite literally, a polyhedron is a three-dimensional object with many faces.
polyhedron. n, pl-drons or-dra (-drÉ). 1. (Mathematics) a solid figure consisting of four or more plane faces (all polygons), pairs of which meet along an edge, three or more edges meeting at a vertex. In a regular polyhedron all the faces are identical regular polygons making equal angles with each other. Specific polyhedrons are named according to the number of faces, such as tetrahedron, icosahedron, etc. [C16: from Greek poluedron, from poly- + hedron side, base]. (ËpÉl iËhi drÉn). n., pl.