Cereal Staple is a term used to describe a type of food that is eaten regularly and is usually a grain-based product. OATS (4 letters) and OAT (3 letters) are both examples of cereal staples, as they are grains that are eaten regularly in many parts of the world. OATS are a popular breakfast food, often served as oatmeal or muesli, and are also used in baking and other recipes. OAT is a type of cereal grain that is used to make oatmeal, porridge, and other dishes.