A cereal is any grass cultivated for the edible components of its grain (botanically, a type of fruit called a caryopsis), which is composed of an endosperm, a germ, and a bran. Cereal grain crops are grown in greater quantities and provide more food energy worldwide than any other type of crop and are therefore staple crops. They include rice, wheat, rye, oats, barley, millet and maize. Edible grains from other plant families, such as buckwheat, quinoa and chia, are referred to as pseudocereals.

In their unprocessed whole grain form, cereals are a rich source of vitamins, minerals, carbohydrates, fats, oils, and protein. When processed by the removal of the bran and germ the remaining endosperm is mostly carbohydrate. In some developing countries, cereals constitute a majority of daily sustenance. In developed countries, cereal consumption is moderate and varied but still substantial, primarily in the form of refined and processed grains. Because of the dietary importance of cereals, the cereal trade is often at the heart of food trade – with many cereals sold as commodities.