A grain is a small, hard, dry seed – with or without an attached hull or fruit layer – harvested for human or animal consumption. A grain crop is a grain-producing plant. The two main types of commercial grain crops are cereals and legumes.. After being harvested, dry grains are more durable than other staple foods, such as starchy fruits (plantains, breadfruit, etc.) and tubers …

A grain is an obsolescent unit of measurement of mass, and in the troy weight, avoirdupois, and Apothecaries' system, equal to exactly 64.798 91 milligrams.It is nominally based upon the mass of a single ideal seed of a cereal.From the Bronze Age into the Renaissance, the average masses of wheat and barley grains were part of the legal definitions of units of mass.

Particle size, also called grain size, means the diameter of individual grains of sediment, or the lithified particles in clastic rocks. The term may also be used for other granular materials. φ scale Size range (metric) Size range (approx. inches) Aggregate name (Wentworth Class) Other names < −8 > 256 mm > 10.1 in