zone

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. BC) 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 23 1/2 °N and 23 1/2 °S, the temperate zones between these parallels and the polar circles (66 1/2 ° 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.

zone The area of the Internet administered by a particular NAME SERVER which forms part of the INTERNET DOMAIN NAME SERVICE. Details of the zone are stored in a FILE known as the ZONE FILE.

zone
1. (biostratigraphic zone) A unit of rock characterized by a clearly defined fossil content. To avoid confusion with other types of zone the term ‘biozone’ (short for ‘biostratigraphic zone’) is preferred by many authorities, although the term ‘biozone’ is also used in a different sense. The term is usually qualified to denote the type of zone. See ACME ZONE; ASSEMBLAGE ZONE; CONCURRENT RANGE ZONE; LINEAGE ZONE; OPPEL ZONE; RANGE ZONE; SUBZONE; TAXON RANGE ZONE; TEILZONE; ZONULE; and INDEX FOSSIL.

2. In crystallography, a set of crystal faces whose intersecting edges are parallel. They are also parallel to, and may be rotated about, a zone axis. See CRYSTAL ZONING.

3. See METAMORPHIC ZONE.