grain drill: see drill.

grain alcohol: see ethanol.

grain, in agriculture, term referring to the caryopsis, or dry fruit, of a cereal grass. The term is also applied to the seedlike fruits of buckwheat and of certain other plants and is used collectively for any plant that bears such fruits. The food content of the seeds (as they are commonly called) is mostly carbohydrate, but some protein, oil, and vitamins are also present. Grain, whole or ground into meal or flour, is the principal food of man and of domestic animals. The seeds of most grains grow in concentrated clusters that are gathered efficiently by modern mechanical harvesting machines (see combine). Grain is easy to handle and, because of its low water content, can be stockpiled and stored for long periods, unlike other starch foods (e.g., the potato). Grains, both living and stored, are attacked by a variety of insect pests (e.g., the corn borer, locust, and grasshopper) and by smuts, rusts, blights, rots, and other diseases of plants. The principal grain crops, in order of total world output, are wheat, rice, Indian corn (or maize), oats, barley, and rye; together, these grains occupy about half of all the land under crops. All the staple grains were domesticated in the Neolithic period, or New Stone Age, and their cultivation was a powerful factor in drawing men into settled communities. Many religious beliefs and rites have been associated with grains; the cereals derive their name from Ceres, the Roman goddess of grain. Grain has been an article of commerce in nearly all civilizations.

grain, in weights and measures: see English units of measurement.

Grain Coast, W Africa, former name of a part of the Atlantic coast that is roughly identical with the coast of modern Liberia. In the 15th cent. "grains of paradise," i.e., seeds of the melegueta pepper, became a major export item; hence the name Grain Coast.

Mass of microscopic spores in a seed plant that appears usually as a fine dust. Each pollen grain is tiny, varies in shape and structure, is formed in the stamens in seed plants, and is transported by various means (see pollination) to the pistil, where fertilization occurs. The outer layer of a pollen grain is very resistant to disintegration; treatment with intense heat, strong acids, or strong bases has little effect on it. Because the grains often are very distinctive, some plant species may be identified by their pollen grains alone. Common components of both recent and ancient geologic sediments, pollen grains have provided much information on the origin and geologic history of plant life on land. Pollen is produced in such quantities that it is a significant part of the airborne components of earth's atmosphere. The protein-containing substance in many pollen grains (e.g., ragweed and many grasses) causes the allergic reaction commonly known as hay fever.

Learn more about pollen with a free trial on Britannica.com.

Storage building for grain, usually a tall frame, metal, or concrete structure with a compartmented interior; also, the device for loading grain into a building. One common mechanism consists of a hopper, a long rectangular open trough, and an endless vertical belt or chain with flights (crosspieces) for conveying the grain to the top of the stack. The force of gravity enables elevated grain to be unloaded quickly and easily from chutes.

Learn more about grain elevator with a free trial on Britannica.com.

or ethyl alcohol or grain alcohol

Organic compound, most important of the alcohols, chemical formula CH₃CH₂OH. Produced by fermentation, it is the intoxicating ingredient in alcoholic beverages. Ethanol for industrial purposes is made by either fermentation or chemical synthesis, then purified by distillation and, to avoid the tax levied on ethyl alcohol for drinking, made unfit to drink (see denaturation) by mixing it with compounds such as methanol, benzene, or kerosene. Ethanol has many uses as a solvent, a raw material, an extraction medium, an antifreeze, an antiseptic, and a gasoline additive and substitute. It is toxic, depressing the central nervous system, and addictive to some persons (see alcoholism). Moderate amounts depress the inhibitory activities of the brain and so appear to stimulate the mind, but larger amounts seriously impair coordination and judgment; excessive consumption can cause coma and death. Taking ethanol in combination with barbiturates or related drugs is especially dangerous.

Learn more about ethanol with a free trial on Britannica.com.

or grain

Any grass yielding starchy seeds suitable for food. The most commonly cultivated cereals are wheat, rice, rye, oats, barley, corn, and sorghum. As human food, cereals are usually marketed in raw grain form or as ingredients of food products. As animal feed, they are consumed mainly by livestock and poultry, which are eventually rendered as meat, dairy, and poultry products for human consumption. They also are used industrially in the production of a wide range of substances, such as glucose, adhesives, oils, and alcohols. Measured in acres planted, wheat is the world's most widely grown cereal crop; rice is the second, but more corn is harvested than either. Grains are generally rich in carbohydrates and energy value but comparatively low in protein and naturally deficient in calcium and vitamin A. Breads are usually enriched to compensate for any nutritional deficiencies in the cereal used. Though often consumed in the areas where grown, cereal and cereal by-products are also major commodities in international trade.

Learn more about cereal with a free trial on Britannica.com.