Cereals, grains or cereal grains, are grasses cultivated for the edible components of their fruit seeds - the endocarp, germ and bran. Cereal grains are grown in greater quantities and provide more food energy worldwide than any other type of crop; they are therefore staple crops. In their natural form (as in whole grain), they are a rich source of vitamins, minerals,carbohydrates, fats and oils, and protein. However, when refined by the removal of the bran and germ, the remainingendocarp is mostly carbohydrate and lacks the majority of the other nutrients. In some developing nations, grain in the form of rice, wheat, or maize (in American terminology, corn) constitutes a majority of daily sustenance. In developed nations, cereal consumption is more moderate and varied but still substantial.

The word cereal derives from Ceres, the name of the Roman goddess of harvest and agriculture.