The term 1, 2, 3 OR R can be solved by the word GEAR. GEAR is a mechanical device consisting of a toothed wheel or cogwheel that meshes with another toothed part in order to transmit torque. It is used to change the speed or direction of an object, or to change the magnitude of a force. Gears are used in many different machines and mechanisms, including automobiles, bicycles, clocks, and other machines.