(pronounced FOH-toh-sellz)

This word can be used in a variety of applications for different industries because the true definition is “an electronic device whose electrical properties are modified by the action of light.” However, in design speak it is used to describe specifically the device used in to detect low levels of light and, thus, cause light fixtures to turn on automatically. Most commonly, photocells are used in exterior lighting applications and nightlights, but sometimes you will find them in units that can plug into a wall socket to control table or floor lamps.