Grains and Legumes

The word grain has several meanings, most being descriptive of a small piece or particle.

Particle-related

The primary definition is the agricultural one, with the others derived from it.

• In agriculture, a grain is the seed of a grass, a simple dry fruit technically called a caryopsis. Such crops are often called cereals. Grain can also refer to other types of small seeds, though this is technically less correct.
• In units of measurement, the grain is a unit of mass equal to 64.79891 milligrams. It was originally based on the weight of one grain of barley. It was used in the past for older drugs such as aspirin, for bullets, and for precious metals.
• In geology, a grain is a single particle of rock or other material, such as sand or salt; see grain size.
• In materials science (especially metallurgy), a grain is a single crystal inside solid-state matter, also referred to as crystallite — related to the obsolete term "corn" as in corned beef.
• In photography, the fineness of image resolution for photographic film (i.e., graininess of a picture), originally related to the (crystallographic) grain size of silver iodide.

Others

• In wood, grain describes the alignment and texture of the wood fibres. This is often important in its effect on woodworking techniques (e.g. going against the grain).
• In golf, the direction in which individual blades of grass lie, usually in reference to a putting green.
• In textiles, grain refers to the direction of woven fabric's warp (lengthwise) and weft (crosswise) threads.
• In rocket science, grain refers to the solid propellant of a rocket (either solid fuelled or hybrid), more or less a hollow cylinder, sometimes textured inside, and possibly very large.
• In computer science, grain refers to the size of code executed by a thread or process before it is interrupted in a multiprocess system (its granularity). Thus we have fine-grained and coarse grained parallelism.
• In physics, a fine-grained description is one which contains a lot of small-scale detail. Reducing the amount of detail gives a coarse-grained description.
• Grain may refer to the place Isle of Grain in Kent, England, on which lies the village of Grain, Kent.
• Grain is one of the stocks in the game Stock Ticker.
• In music, see granular synthesis.

Varieties of soybean seeds, a popular legume

A flowering legume (Lupin)

The term legume has two closely related meanings in botany, a situation encountered with many botanical common names of useful plants whereby an applied name can refer to either the plant itself, or to the edible fruit (or useful part). Thus, "legume" can be:

• The common name for plant species in the Family Fabaceae (or Leguminosae);
• The name of a type of fruit, characteristic of legumous plants. To wit:

A legume is a simple dry fruit which develops from a simple carpel and usually dehisces (opens along a seam) on two sides. A common name for this type of fruit is a "pod", although pod is also applied to a few other fruit types. Well-known plants that bear legume fruits include alfalfa, clover, peas, beans, lupins and peanuts. A peanut is not a nut in the botanical sense; a peanut is an indehiscent legume, that is, one that does not spontaneously split open along a seam.

Legumes are noteworthy for their ability to fix atmospheric nitrogen, an accomplishment attributable to a symbiotic relationship with certain bacteria known as rhizobia found in root nodules of these plants. The ability to form this symbiosis reduces fertilizer costs for farmers that grow legumes, and means that legumes can be used in a crop rotation to replenish soil that has been depleted of nitrogen.

Legume seed and foliage has a comparatively higher protein content than non-legume material, probably due to the additional nitrogen that legumes receive through nitrogen-fixation symbiosis. This high protein content makes them desirable crops in agriculture. Farmed legumes fall into two classes: forage and grain. Forage legumes, like alfalfa, clover and vetch, are sown in pasture and grazed by livestock. Grain legumes are cultivated for their seeds, and are also called pulses. The seeds are used for human and animal consumption or for the production of oils for industrial uses. Grain legumes include beans, lentils, lupins, peas, peanuts and soybeans.

The term is derived from the French word "légume" (which, however, has a wider meaning and refers to any kind of vegetable).

External links

• AEP - European association for grain legume research
• Mediterrasian - Article discussing health benefits of eating legumes