In general, any combination of bodies so connected that their relative motions are constrained, and by means of which force and motion may be transmitted and modified, as a screw and its nut, or a lever arranged to turn about a fulcrum or a pulley about its pivot, etc.; especially, a construction, more or less complex, consisting of a combination of moving parts, or simple mechanical elements, as wheels, levers, cams, etc., with their supports and connecting framework, calculated to constitute a prime mover, or to receive force and motion from a prime mover or from another machine, and transmit, modify, and apply them to the production of some desired mechanical effect or work, as weaving by a loom, or the excitation of electricity by an electrical machine. Note: The term machine is most commonly applied to such pieces of mechanism as are used in the industrial arts, for mechanically shaping, dressing, and combining materials for various purposes, as in the manufacture of cloth, etc. Where the effect is chemical, or other than mechanical, the contrivance is usually denominated an apparatus or device, not a machine; as, a bleaching apparatus. Many large, powerful, or specially important pieces of mechanism are called engines; as, a steam engine, fire engine, graduating engine, etc. Although there is no well-settled distinction between the terms engine and machine among practical men, there is a tendency to restrict the application of the former to contrivances in which the operating part is not distinct from the motor.