Grains are small, hard, dry
seeds, with or without attached
hulls or
fruit layers, harvested for human or animal consumption. Agronomists also call the plants producing such seeds "grain crops". The two main types of commercial grain crops are
cereals such as
wheat and
rye, and
legumes such as
beans and
soybeans. Ubiquity of grain as a food source encouraged use of the term to describe other particles with
volume or
mass similar to an individual seed.