Cheesecloth is a type of thin, porous fabric that is commonly used in cooking and baking. It's made from cotton or other natural fibers and has a very fine weave, which allows it to be used as a sieve for straining liquids or separating solids from liquids. The name comes from its traditional use in making cheese - the cloth is placed over a mold to drain off excess liquid, allowing the curd to form more easily. Today, cheesecloth is also commonly used to wrap foods while cooking, such as fish or vegetables, to add flavor and moisture. It's available in various sizes and can be found in most grocery stores or online retailers.