In geography, regions, otherwise referred to as areas, zones, lands or territories, are portions of the Earth's surface that are broadly divided by physical characteristics (physical geography), human impact characteristics (human geography), and the interaction of humanity and the environment (environmental geography). Geographic regions and sub-regions are mostly described by their imprecisely defined, and sometimes transitory boundaries, except in human geography, where jurisdiction areas such as national borders are defined in law. More confined or well bounded portions are called locations or places.
Apart from the global continental regions, there are also hydrospheric and atmospheric regions that cover the oceans, and discrete climates above the land and water masses of the planet. The land and water global regions are divided into subregions geographically bounded by large geological features that influence large-scale ecologies, such as plains and features.
As a way of describing spatial areas, the concept of regions is important and widely used among the many branches of geography, each of which can describe areas in regional terms. For example, ecoregion is a term used in environmental geography, cultural region in cultural geography, bioregion in biogeography, and so on. The field of geography that studies regions themselves is called regional geography. Regions are an area or division, especially part of a country or the world having definable characteristics but not always fixed boundaries.
In the fields of physical geography, ecology, biogeography, zoogeography, and environmental geography, regions tend to be based on natural features such as ecosystems or biotopes, biomes, drainage basins, natural regions, mountain ranges, soil types. Where human geography is concerned, the regions and subregions are described by the discipline of ethnography.