A knife (plural knives) is a tool with a cutting edge or blade which may or may not be be attached to a handle. Cutting implements, such as those used in mechanical food processors are similarly referred to as knives. The blade edge can be tapered or serrated, or a combination of both. Single-edged knives may have a reverse edge or false edge. These edges are usually serrated and are used to further enhance function. Knife blades can be manufactured from a variety of materials.