A stain is a discoloration that distinguishes itself from the material on which it is found. It can be unintentional, in the case of domestic stains on fabric, cloth, or other material, or it can be intentional. It is caused by the drying of a liquid or food.
Stain resistance is an important characteristic in modern textile engineering. Various laundry techniques exist to attempt to remove or minimize existing stains, and stain removers are an important type of chemical in laundry detergents.