A microscale machine that can sense information from the environment and act accordingly. Outside the U.S., it can also refer to microelectromechanical systems (MEMS).
In Bronfenbrenner's ecological systems theory, the immediate environment provided in such settings as the home, school, workplace, and neighborhood.
Microsystem is the name commonly used in Europe to describe the same technology which goes under the name MEMS (Micro Electro Mechanical Systems) in the US. In Japan, this field is often termed micromachines.