The circular saw is a machine using a toothed metal cutting disc or blade. The term is also loosely used for the blade itself. The blade is a tool for cutting wood or other materials and may be hand-held or table-mounted. It can also be used to make narrow slots (dados). Most of these saws are designed with a blade to cut wood but may also be equipped with a blade designed to cut masonry, plastic, or metal. There are also purpose-made circular saws specially designed for particular materials. While today circular saws are almost exclusively powered by electricity, larger ones, such as those in "saw mills", were traditionally powered by water turning a large wheel.