A round object is an object that has a circular shape. The term can refer to four different objects: a BALL, a DISC, an ORB, and a SPHEROID. A BALL is a solid or hollow SPHERE, usually made of rubber, leather, or plastic. A DISC is a flat, round object, often made of metal or plastic. An ORB is a spherical object, usually made of glass or metal. A SPHEROID is an object that is shaped like a SPHERE but is not perfectly round. Finally, a SPHERE is a perfectly round object.