Microelectromechanical systems. A technology in which both electronic and mechanical components make up a microscopic machine. This term is used most in the context of semiconductor production. In watchmaking, MEMS refers to the application of the MEMS fabrication technology of photolithography to the manufacture of watch components. Photolithography utilizes light to lay down a thin protective layer over a substrate so that the uncovered areas can be etched away. This method is ideal for making intricate microscopic components and produces far more precise and smaller products than those made with traditional metalworking techniques such as cutting, milling, stamping, or casting. Thus it can be used to create the smallest and most important components of wristwatches. The technology is most associated with Japanese watchmaker Seiko.