Microengineering and Microelectromechanical systems (MEMS) have very few watertight definitions regarding their subjects and technologies. Microengineering can be described as the techniques, technologies, and practices involved in the realization of structures and devices with dimensions on the order of micrometers. MEMS often refer to mechanical devices with dimensions on the order of micrometers fabricated using techniques originating in the integrated circuit (IC) industry, with emphasis on silicon-based structures and integrated microelectronic circuitry. However, the term is now used to refer to a much wider range of microengineered devices and technologies.
There are other terms in common use that cover the same subject with slightly different emphasis. Microsystems technology (MST) is a term that is commonly used in Europe. The emphasis tends towards the development of systems, and the use of different technologies to fabricate components that are then combined into a system or device is more of a feature of MST than MEMS, where the emphasis tends towards silicon technologies.