The word pneumatic originally comes from Greek. The specific Greek word is pneuma, one which signifies "air, wind or breath." In essence, the use of wind to man's advantage is a long standing one. Evidence of this can be seen in the invention of the sail for sea-going vessels or even in the dart or blowguns used by indigenous peoples around the globe. In later centuries this extended to balloons. The human manipulation of air power now extends to widespread technologies.
In mechanical terms, pneumatics is part of a system that produces power. What distinguishes pneumatics from other disciples is that it uses gases, sometimes air, to actually create that power. This is different from hydraulics, which uses liquids, such as water or oil, to accomplish this task. A pneumatic system depends on what is called differential pressure or a pressure differential. A system equipped with a pressure differential has at least two points: one where the pressure is higher and the other lower. You may think of the inlet and outlet pieces of a pump as an example.
Again, pneumatics are associated primarily with systems. A system in this context is described by John Pannel as a "complete set of parts working together." He lists the following as some of the more common pieces of mechanics that comprise systems equipped with pneumatically-driven power supplies: compressors, storage tanks, solenoids, valves, actuators, regulators and gauges. The compressor is the agent for converting electrical current into pneumatic-power potential. This compressor, as Pannel suggests, is the very "heart of the system."
Besides being found in many industrial or professional settings, pneumatic tools are also used for household applications. You can find pneumatic hand drills on the market in addition to items such as saws, sanders, nailers and wrenches. An air compressor is required for the use of a pneumatic tool. However, Popular Mechanics suggests that the consumer look for one of the many available combination packages that are provided by selected manufacturers. These packs often supply both the tool as well as the needed compressor and supplemental air hoses involved in assembly and use.