region

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A large, usually continuous segment of a surface or space.
• noun A portion of the earth's surface distinguished from others by some characteristic.
• noun A bioregion.
• noun A political district or unit, often with its adjacent lands.
• noun An area of the body having natural or arbitrarily assigned boundaries.
• noun An area of interest or activity; a sphere.
• noun An approximate degree or amount.

from The Century Dictionary.

• noun In the plan of excavations at Pompeii, one of the primary divisions introduced by Fiorelli about 1860. The arrangement is based on a misconception but has nevertheless been retained. Each region contains several blocks or insulæ.
• noun In phytogeography: A mountain belt marked by peculiar floral types; an altitudinal zone. Thus used by Humboldt, who for the equatorial district of the Andes distinguished nine such regions. Schimper also prefers this term to zone in treating of mountain belts. He distinguishes, on purely œcological grounds, basal, montane, and alpine mountain regions.
• noun A comprehensive territorial unit with sufficient uniformity of conditions to secure uniformity in vegetation. A region will include several formations and will itself be included in some larger unit, as a realm.
• noun For a special use, see life zone.
• noun Any considerable and connected part of a space or surface; specifically, a tract of land or sea of considerable but indefinite extent; a country; a district; in a broad sense, place without special reference to location or extent: as, the equatorial regions; the temperate regions; the polar regions; the upper regions of the atmosphere.
• noun An administrative division of a city or territory; specifically, such a division of the city of Rome and of the territory about Rome, of which the number varied at different times; a district, quarter, or ward (modern rione).
• noun Figuratively, the inhabitants of a region or district of country.
• noun In anatomy, a place in or a part of the body in any way indicated: as, the abdominal regions.
• noun Place; rank; station; dignity.
• noun Specifically, the space from the earth's surface out to the orbit of the moon: properly called the elemental region.
• noun In zoögeog., a large faunal area variously limited by different authors.
• noun Of the thorax, same as inframammary region.
• noun Synonyms Quarter, locality, clime, territory.

from the GNU version of the Collaborative International Dictionary of English.

• noun One of the grand districts or quarters into which any space or surface, as of the earth or the heavens, is conceived of as divided; hence, in general, a portion of space or territory of indefinite extent; country; province; district; tract.
• noun Tract, part, or space, lying about and including anything; neighborhood; vicinity; sphere.
• noun obsolete The upper air; the sky; the heavens.
• noun The inhabitants of a district.
• noun Obs. or R. Place; rank; station.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun Any considerable and connected part of a space or surface; specifically, a tract of land or sea of considerable but indefinite extent; a country; a district; in a broad sense, a place without special reference to location or extent but viewed as an entity for geographical, social or cultural reasons.
• noun An administrative subdivision of a city, a territory, a country or the European Union.
• noun historical Such a division of the city of Rome and of the territory about Rome, of which the number varied at different times; a district, quarter, or ward.
• noun figuratively The inhabitants of a region or district of a country.
• noun anatomy A place in or a part of the body in any way indicated.
• noun obsolete Place; rank; station; dignity.
• noun obsolete The space from the earth's surface out to the orbit of the moon: properly called the elemental region.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a part of an animal that has a special function or is supplied by a given artery or nerve
• noun a large indefinite location on the surface of the Earth
• noun the extended spatial location of something
• noun the approximate amount of something (usually used prepositionally as in `in the region of')
• noun a knowledge domain that you are interested in or are communicating about