zone [Gr.,=girdle], in geography, area with a certain physical and/or cultural unity that distinguishes it from other areas. The division of the earth into five climatic zones probably originated (5th cent. B.C.) with Parmenides, who recognized a torrid zone (see tropics) and north and south temperate zones and postulated north and south frigid (or arctic) zones; his classification was adopted by Aristotle and is still in use. The zones are based on latitude: the torrid zone lies between 231/2°N and 231/2°S, the temperate zones between these parallels and the polar circles (661/2° N and S), and the frigid zones from the polar circles to the poles. Later geographers, recognizing that climate is affected by such conditions as altitude, distance from water, prevailing winds, and ocean currents, have used other bases for zoning. Most geographers today recognize five major climatic groups, based mainly on the work of the German meteorologist Wladimir Köppen. Two of these groups—the rainy tropics and the dry tropics, which encompass four different climates—together correspond roughly to the former torrid zone. Two humid climate groups of the Köppen system, encompassing six climates, together correspond roughly to the former temperate zones. Köppen's two polar climates correspond roughly to the two former frigid zones. In addition to the five groups encompassing twelve climates, geographers also recognize a series of highland zones where many of the other climates of the world are duplicated. Geographic zones in which people have similar patterns of life are called culture zones or areas (see culture). An example would be the plains area of North America.

Any of a group of techniques used to purify an element or a compound or to control its composition by melting a short region (called a zone) and causing this liquid zone to travel slowly through a relatively long ingot, or charge, of the solid. In zone refining, the most important of the zone-melting techniques, a solid is refined by multiple molten zones being passed through it in one direction. Each zone carries a fraction of the impurities to the end of the solid charge, thereby purifying the remainder. Zone refining is particularly important as a method of purifying crystals, especially for use in semiconductor devices.

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Long, narrow, and mountainous submarine lineation that generally separates ocean-floor ridges differing in depth by as much as 1 mi (1.6 km). The largest fracture zones, in the eastern Pacific, are more than 1,000 mi (1,600 km) long and 60–125 mi (100–200 km) wide. Numerous shorter fracture zones in the Atlantic are associated with the Mid-Atlantic Ridge.

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Oceanic trench area in which, according to the theory of plate tectonics, the seafloor underthrusts an adjacent plate, dragging the accumulated trench sediments downward into the Earth's upper mantle. Seealso deep-sea trench.

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Area within which goods may be landed, handled, and re-exported freely. The purpose is to remove obstacles to trade and to permit quick turnaround of ships and planes. Only when the goods are moved to consumers within the country in which the zone is located do they become subject to tariffs and customs regulation. Free-trade zones are found around major seaports, international airports, and national frontiers; there are more than 200 such zones in the U.S. alone.

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Region of apparent absence of galaxies near the plane of the Milky Way Galaxy. Millions of external galaxies are in this region of the sky but are obscured by interstellar dust within the Milky Way. The zone's obscuration can be penetrated at the infrared portion of the electromagnetic spectrum. Seealso infrared astronomy.

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or Panama Canal Zone

Strip of territory, a historic administrative entity in Panama over which the U.S. formerly exercised jurisdictional rights (1903–79). The zone came into being in 1904 when Panama granted the U.S., in return for annual payments, sole right to operate and control the Panama Canal, including a strip of land 10 mi (16 km) wide along the canal extending from the Atlantic to the Pacific Ocean and bisecting the Isthmus of Panama. The zone was abolished by treaty in 1979, and civil control of the territory was returned to Panama. By the same treaty a commission under joint U.S.-Panamanian ownership was established to operate the canal until the year 2000, when Panama assumed full control.

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Zone may refer to:

In geography:

  • One of five geographical zones of the earth:
  • Hardiness zone, in gardening and other agriculture a geographically-defined zone in which a specific category of plant life is capable of growing
  • "The zone" (die (Ost)Zone in German), a derogatory term for the German Democratic Republic
  • Zone (BS), a town and comune in the Province of Brescia, Lombardy, Italy
  • Zone of alienation, the exclusion zone around the site of the Chernobyl disaster
  • Zones (permaculture), a method of planning civil/agricultural placement
  • Zone, in zone pricing, a geographical area in which charges are constant
  • Zoning, in urban planning, a system of land-use regulation

In entertainment:

In sports:

In technology:

  • DNS zone, a portion of the namespace in the Domain Name System
  • Fibre Channel zoning, a method for facilitating low interference and high security in computer data storage systems
  • Solaris Zones, one component of the Solaris Containers virtualization feature
  • A thermal zone, or just zone, in heating, ventilating, and air-conditioning (HVAC)
  • Zone, a short name for DVD region code

In other uses:

  • Erogenous zone, an area on the body which is sexually stimulating
  • "The zone", or flow, a mental state attained by a person fully immersed in some activity
  • Zone diet, a diet that involves precise proportions by weight of protein, fat and carbohydrate
  • Zone system, a photographic technique for determining optimal film exposure and development
  • Zone (vestment), a belt worn by priests and bishops of the Eastern Orthodox Church

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