Grain

A grain is a small, hard, dry fruit (caryopsis) – with or without an attached hull 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 (sweet potatoes, cassava, and more). This durability has made grains well suited to industrial agriculture, since they can be mechanically harvested, transported by rail or ship, stored for long periods in silos, and milled for flour or pressed for oil. Thus, the grain market is a major global commodity market that includes crops such as maize, rice, soybeans, wheat and other grains.
In the grass family, a grain (narrowly defined) is a caryopsis, a fruit with its wall fused on to the single seed inside, belonging to a cereal such as wheat, maize, or rice. More broadly, in agronomy and commerce, seeds or fruits from other plant families are called grains if they resemble cereal caryopses. For example, amaranth is sold as "grain amaranth", and amaranth products may be described as "whole grains". The pre-Hispanic civilizations of the Andes had grain-based food systems, but at higher elevations none of the grains belonged the cereal family. All three grains native to the Andes (kaniwa, kiwicha, and quinoa) are broad-leaved plants rather than grasses.
Many different species of cereal are cultivated for their grains.
Starchy grains from broadleaf (dicot) plant families are cultivated as nutritious alternatives to cereals. The three major pseudocereal grains are:
Pulses or grain legumes, members of the pea family, have a higher protein content than most other plant foods, at around 20%, while soybeans have as much as 35%. As is the case with all other whole plant foods, pulses also contain carbohydrates and fat. Common pulses include:
Oilseed grains are grown primarily for the extraction of their edible oil. Vegetable oils provide dietary energy and some essential fatty acids. They are also used as fuel and lubricants.
Because grains are small, hard and dry, they can be stored, measured, and transported more readily than can other kinds of food crops such as fresh fruits, roots and tubers. The development of grain agriculture allowed excess food to be produced and stored easily which could have led to the creation of the first temporary settlements and the division of society into classes.
This assumption that grain agriculture led to early settlements and social stratification has been challenged by James Scott in his book Against the Grain. He argues that the transition from hunter-gatherer societies to settled agrarian communities was not a voluntary choice driven by the benefits of increased food production due to the long storage potential of grains, but rather that the shift towards settlements was a coerced transformation imposed by dominant members of a society seeking to expand control over labor and resources.
Those who handle grain at grain facilities may encounter numerous occupational hazards and exposures. Risks include grain entrapment, where workers are submerged in the grain and unable to extricate themselves; explosions caused by fine particles of grain dust, and falls.