equatorial belt of calms: see doldrums.

belt, girdle or band worn around the body, originally to confine loose garments. Later the girdle became a decorative accessory and was used to carry belongings. The Greeks and Romans wore ornamental cords and bands of many materials, including metal. The medieval belt displayed brilliant goldwork and gems; it carried the purse, dagger, sword, and other personal belongings of the wearer. Since then the belt has varied in style and importance. It has been symbolic of strength, of alertness, and of integrity. In folklore belts have often been accorded supernatural power.

Sun Belt or Sunbelt, southern tier of the United States, focused on Florida, Texas, Arizona, and California, and extending as far north as Virginia. The term gained wide use in the 1970s, when the economic and political impact of the nation's overall shift in population to the south and west became conspicuous. Areas near the Mexican border have received millions of immigrants since the 1960s. Economic growth in many Sun Belt cities since World War II has stimulated interregional migration from the NE United States and the Rust Belt; by 1990, Los Angeles, San Diego, Phoenix, Houston, Dallas, and San Antonio were among the ten largest cities in the United States. During the 1990s the fastest growing cities in the United States were in the Sun Belt. The warm climate has attracted large retirement communities, especially in Florida and Arizona. In addition, the birth rate in the Sun Belt is about 10% greater than that in the rest of the country. Attracted by the relative lack of labor unions and the prospect of cheaper labor than was generally available in the north, manufacturers began to locate in the Southeast in significant numbers after World War II; aerospace firms and defense contractors were drawn to the vicinity of military bases in S California and throughout the Southwest. Texas, Louisiana, and Oklahoma benefited from the oil booms of the 1970s. In addition, the enormous tourist industries of the Sun Belt (especially Florida and S California) have brought the region considerable wealth. Although overall the expansion of the Sun Belt's economy in recent decades has been dramatic, the distribution of the region's prosperity has been uneven; of the 25 metropolitan areas with the lowest per capita income in 1990, 23 were in the Sun Belt. The rapid fall of oil prices in the 1980s hurt the economies of the energy-producing areas of the Sun Belt; Houston was especially hard hit. By the 1980s, the Los Angeles area, beset by problems ranging from air pollution to a growing population of unskilled immigrants, came increasingly to resemble some of the troubled metropolitan areas of the North. Politically, the rise of the Sun Belt has generally been viewed as advantageous to the Republican party, especially in presidential elections. Since 1970, the Sun Belt has gained more than 25 electoral votes, mostly at the expense of the Northeast and Midwest.

Rust Belt or Rustbelt, economic region in the NE quadrant of the United States, focused on the Midwestern (see Midwest) states of Illinois, Indiana, Michigan, and Ohio, as well as Pennsylvania. The term gained wide use in the 1970s as the formerly dominant industrial region became noted for the abandonment of factories, unemployment, outmigration, the loss of electoral votes, and overall decline. Since the 1960s, manufacturing cities throughout the Great Lakes region and in the Northeast have suffered a decline in population and economic strength as manufacturers relocated, primarily to the Sun Belt, overseas, or more recently, to Mexico. Meanwhile, the nation as a whole has shifted toward a service economy. Detroit, although still one of the world's largest manufacturing centers, has been especially hard hit and unable to reduce its dependence on the manufacturing sector. Suburban flight induced by the decline of the central city has been dramatic in large cities such as St. Louis and Cleveland, as well as smaller cities like Gary, Ind., and Akron, Ohio. By the 1980s, the economy of some Rust Belt cities had noticeably improved after the introduction or expansion of non-manufacturing industries. Pittsburgh, initially devastated by cutbacks in its steel industry as early as the late 1950s, has since emphasized its role as a center for research and development and finance.

Little Belt: see Store Bælt and Lille Bælt, straits, Denmark.

Kuiper belt: see comet; Kuiper, Gerard Peter.

Great Belt: see Store Bælt and Lille Bælt, straits, Denmark.

Cotton Belt, former agricultural region of the SE United States where cotton was the main cash crop throughout the 19th and much of the 20th cent. Located on the Atlantic and Gulf coastal plains and on the Piedmont upland, it extended through North Carolina, South Carolina, Georgia, Alabama, Mississippi, W Tennessee, E Arkansas, Louisiana, E Texas, and S Oklahoma, and also into small areas of SE Missouri, SW Kentucky, N Florida, and SE Virginia. Cotton is still grown in certain parts of the region but has ceased to be the dominant crop. The intensive production of corn, wheat, soybeans, peanuts, beans, and livestock has largely replaced cotton. Commercial timber production is also widespread on many former cotton plantations. Until the invention of the cotton gin in 1793, the Cotton Belt was confined to the coastal areas of South Carolina and Georgia; by the mid-1800s, it extended from S Virginia to E Texas. The belt's climatic conditions allowed cotton to thrive, but post-Civil War reforms, soil depletion, and the boll weevil (a type of beetle that eats cotton) combined to push cotton west. Today large quantities of cotton also are grown are irrigated land in the Southwest—W Texas, S New Mexico, S Arizona, and S California (see Black Belt; Imperial Valley). The dryness of those areas makes it easier to control insect pests. Texas, Mississippi, Georgia, and Arkansas are the leading producers of the old cotton belt; California ranks after Texas nationally.

Corn Belt, major agricultural region of the U.S. Midwest where corn acreage once exceeded that of any other crop. It is now commonly called the Feed Grains and Livestock Belt. Located in the north central plains, it is centered in Iowa and Illinois and extends into S Minnesota, SE South Dakota, E Nebraska, NE Kansas, N Missouri, Indiana, and W Ohio. Large-scale commercial and mechanized farming prevails in this region of deep, fertile, well-drained soils and long, hot, humid summers. The belt produces much of the U.S. corn crop, but agriculture has diversified; soybeans are an important yield. Winter wheat and alfalfa are also significant crops in the area.

Black Belt, term applied to several areas of Mississippi and Alabama, the heart of the Old South, which are characterized by black soil and excellent cotton-growing conditions. The Black Belt area was historically important as the nation's main cotton producer in the mid-1800s. Soil depletion, erosion, the boll weevil, and economic conditions combined to eliminate cotton from the region. Livestock, peanuts, and soybeans have become the area's chief crops.

Belt, Great, and Little Belt, straits: see Store Bælt and Lille Bælt, straits, Denmark.

One of various devices that provide mechanized movement of material, as in a factory. Conveyor belts are used in industrial applications and also on large farms, in warehousing and freight-handling, and in movement of raw materials. Belt conveyors of fabric, rubber, plastic, leather, or metal are driven by a power-operated roll mounted underneath or at one end of the conveyor. The belt forms a continuous loop and is supported either on rollers (for heavy loads) or on a metal slider pan (if loads are light enough to prevent frictional drag on the belt). Motors operating through constant- or variable-speed reduction gears usually provide the power.

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Pair of pulleys attached to usually parallel shafts and connected by an encircling flexible belt (band) that can serve to transmit and modify rotary motion from one shaft to the other. Most belt drives consist of flat leather, rubber, or fabric belts running on cylindrical pulleys or of belts with a V-shaped cross section running on grooved pulleys. Another type of belt, used on some internal-combustion engines for connecting the crankshaft and camshafts, is the toothed (or timing) belt, a flat belt with evenly spaced transverse teeth that fit in matching grooves on the periphery of the pulley.

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or Edgeworth-Kuiper belt

Disk-shaped belt of billions of small icy bodies orbiting the Sun beyond the orbit of Neptune, mostly at distances 30–50 times Earth's distance from the Sun. Gerard Peter Kuiper (1905–73) proposed the existence of this large flattened distribution of objects in 1951 in connection with his theory of the origin of the solar system (see solar nebula). Kenneth Edgeworth (1880–1972) independently had made similar proposals in 1943 and 1949. Whether the belt extends thinly as far as the Oort cloud is not known. Gravitational disturbances by Neptune of objects in the belt are thought to be the origin of most short-period comets. The first Kuiper belt object was discovered in 1992; the orbit, icy composition, and diminutive size of Pluto qualify this body, formerly considered a planet, as a giant Kuiper belt object.

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Traditional area, midwestern U.S. Roughly covering western Ohio, Indiana, Illinois, Iowa, southern Minnesota, eastern South Dakota, Missouri, eastern Nebraska, and eastern Kansas, it is a region in which corn and soybeans are the dominant crops. Many farms are family-operated and average more than 300 acres (120 hectares). Despite the name, the region is agriculturally diverse, raising various feed-grains and livestock.

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