Cereal crops are mostly grasses cultivated for their edible grains or seeds (i.e., botanically a type of fruit called a caryopsis). Cereal grains are grown in greater quantities and provide more energy worldwide than any other type of crop; they are therefore staple crops. They are also a rich source of carbohydrate. In some developing nations, grain constitutes practically the entire diet of poor people. In developed nations, cereal consumption is more moderate but still substantial.
The word cereal derives from Ceres, the name of the Roman goddess of harvest and agriculture. Grains are traditionally called corn in the United Kingdom and Ireland, though that word became specified for maize in the United States, Canada, New Zealand, and Australia.