Environmental Protection. Didymo (Didymosphenia geminata), also known as rock snot, is a non-native invasive microscopic algae (diatom) that can produce large amounts of stalk material to form thick brown mats on stream bottoms. Didymo threatens aquatic habitat, biodiversity and recreational opportunities.
peripheral device - (computer science) electronic equipment connected by cable to the CPU of a computer; disk drives and printers are important peripherals.
Peripheral: Situated away from the center, as opposed to centrally located. For example, peripheral vision means the type of vision that allows one to see objects that are not in the center of one's visual field. The word peripheral comes from the Greek peripheria (peri-, around or about + pherein, to bear, carry). An IV (intravenous) catheter is a peripheral line.