Micro Electro-Mechanical Systems (MEMS) – the technology of the very small, yet not within the realm of Molecular nanotechnology.
Micro Electro-Mechanical Systems refer to "micro devices". These micro devices generally range in size from a micron (a millionth of a meter) to a millimeter (a thousandth of a meter). They are fabricated using modified silicon fabrication technology (used to make electronics), molding and plating, electro discharge machining (EDM), and other technologies capable of manufacturing very small devices.
Common applications are the inkjet printers on many home and office desks, which uses MEMS actuators to deposit the ink on the paper; the accelerometers in modern cars used to deploy airbags in collision accidents; car tire pressure sensors; and small motion sensors. The DLP video projection technology is a MEMS device. MEMS sometimes go by the names micromechanics, micro machines, or micro system technology (MST). MEMS technology is used for optical switching technology for data communications.
Nano devices generally refer to devices ranging in size from a nanometer (a billionth of a meter) to a micron. The nano and MEMS field can overlap.