A machine is any device that uses energy to perform some action. In common usage, the meaning is that of a device having parts that perform or assist in performing any type of work. A simple machine is a device that transforms the direction or magnitude of a force without consuming any energy. The word "machine" is derived from the Latin machina.
Historically, a device required moving parts to be classified as a machine; however, the advent of electronics technology has led to the development of devices without moving parts that are considered machines—the computer being the most obvious example.
"Engines" are machines that convert heat or other forms of energy into mechanical energy. For example, in an internal combustion engine the expansion of gases caused by the heat from an exothermic chemical reaction results in a force being applied to a movable component, such as a piston or turbine blade.
Machines are ubiquitous in a wide variety of industrial, commercial, residential and transportation applications. Those employing hydraulics are especially useful in manufacturing and construction applications that require mechanisation.