To reduce a large piece of food to small particles or thin shreds by rubbing it against a coarse, serrated surface, usually on a kitchen utensil called a grater. A food processor fitted with the metal blade can also be used to reduce food to small bits or, fitted with the shredding disc, to long, thin strips. The food to be grated should be firm, which in the case of cheese can usually be accomplished by refrigeration. Grating food makes it easier to incorporate with other foods.