Glossary of Geography Terms

What's inside

absolute location

The particular location of a point on the Earth's surface that can be expressed by a grid reference such as latitude and longitude.[[1]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-OERI_1996-1)

accessibility

A locational characteristic that permits a place to be reached by the efforts of those at other places.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

accessibility resource

A naturally emergent landscape form that eases communication between areas.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

active volcano

A volcano that is currently erupting, or one that has erupted within the last 10,000 years (the Holocene) or during recorded history.[[3]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-USGS_2010-3)

affluent

See [tributary](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#tributary).

agricultural geography

A sub-discipline of geography which studies the spatial relationships between humans and agriculture and the cultural, political, and environmental processes that lead to parts of the Earth's surface being transformed by humans through primary sector activities into agricultural landscapes.

alluvial fan

A distinctly triangular, fan-shaped deposit of sediment transported by water, often referred to as alluvium. Alluvial fans usually form at the base of mountains, where high-velocity rivers or streams meet a relatively flat area and lose the energy needed to carry large quantities of sediment, which ultimately spreads out in all available directions. They tend to be larger and more obvious in arid regions.

alluvial plain

A wide, flat, gently sloping plain created by the long-term deposition of alluvium from one or more rivers flowing from highland regions, and typically characterized by various fluvial landforms such as braided streams, terraces, and meanders. Alluvial plains encompass the larger area over which a river's floodplain has shifted through geological time.

alluvial soils

Soils deposited through the action of moving water. These soils lack horizons and are usually highly fertile.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

alluvium

Clay, silt, gravel, or similar detrital material deposited by running water.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

altitude

The height of an object in the atmosphere above sea level. Compare [elevation](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#elevation).[[1]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-OERI_1996-1)

Antarctic

The region of the Earth that is south of the Antarctic Circle.

Antarctic Circle

The southernmost of the Earth's two polar circles of latitude, south of which the sun appears above the horizon for 24 continuous hours at least once per year (and is therefore visible at midnight) and also appears at least partially below the horizon for 24 continuous hours at least once per year (and is therefore not visible at noon). Its latitude is approximately 66°33′47.1″ south of the Equator. Contrast [Arctic Circle](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#arctic_Circle).

anthropization

The conversion of open spaces, landscapes, and natural environments by human action.

anticline

A geological fold that has an arch-like convex shape and its oldest beds near its center, often visible at the Earth's surface in exposed rock strata.

antimeridian

The line of longitude exactly 180 degrees east or west of the Prime Meridian, with which it forms a great circle dividing the Earth into the Eastern and Western Hemispheres. It is used as the approximate basis for the International Date Line because it mostly passes through the open waters of the Pacific Ocean.

antipodes

Any pair of points on the Earth's surface that are diametrically opposite to each other, such that a straight line connecting them would pass through the Earth's center. Such points are as far away from each other as possible, with the great-circle distance between them being approximately 20,000 kilometres (12,000 mi).

apparent place

The apparent position of an object in space as seen by an observer, which, because of physical and geometric effects, may differ from the object's true position.

aquifer

An underground layer of water-bearing permeable rock, rock fractures, or unconsolidated materials such as gravel, sand, or silt.

archipelago

A collection of islands in a sea.

arête

A sharp, narrow mountain ridge, often resulting from the erosive activity of alpine glaciers flowing in adjacent valleys.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

arroyo

A deep gully cut by a stream that flows only part of the year; a dry gulch. The term is used primarily in desert areas.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

Arctic

The region of the Earth that is north of the Arctic Circle.

Arctic Circle

The northernmost of the Earth's two polar circles of latitude, north of which the sun appears above the horizon for 24 continuous hours at least once per year (and is therefore visible at midnight) and also appears at least partially below the horizon for 24 continuous hours at least once per year (and is therefore not visible at noon). Its latitude is approximately 66°33′47.1″ north of the Equator. Contrast [Antarctic Circle](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#antarctic_Circle).

ash

Fragments of lava or rock less than 1⁄3 centimetre (0.13 in) in diameter that have been ejected into the atmosphere by a volcanic explosion.[[3]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-USGS_2010-3)

Atlantic Seaboard fall line

The physiographic border between the Piedmont and Atlantic coastal plain regions of eastern North America. The name derives from the river rapids and falls that occur as the water flows from the hard rocks of the higher piedmont onto the softer rocks of the coastal plain.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

atlas

A bound collection of maps.[[1]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-OERI_1996-1)

atmosphere

The mixture of gases, aerosols, solid particles, and water vapor that envelops the Earth.[[3]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-USGS_2010-3)

atoll

A ring-shaped coral reef that partially or completely encircles a lagoon.

ayre

Another name for a shingle beach or other gravel-covered spit, bar, or tombolo, used primarily in the archipelagos of northern Scotland.

azimuth

The angle formed between a reference vector (often magnetic north) and a line from the observer to a point of interest projected perpendicularly to the zenith on the same plane as the reference vector. Azimuth is usually measured in degrees and can be determined with a compass.

backwater

A part of a river in which there is little or no current.

badlands

An area of rugged or irregular topography resulting from extensive wind and water erosion of sedimentary rock.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

bajada

Also spelled bahada.

A series of adjacent alluvial fans coalescing in a basin at the foot of a mountain range.

bar

An elevated region of sediment such as sand or gravel which has been deposited by the flow of a river or other moving body of water. See also [shoal](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#shoal).

barrier ridge

Any steep, unnavigable ridge or escarpment isolating one terrain from another.

base level

The lowest level to which a stream can erode its bed. The ultimate base level of all streams is the sea.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

basin

See [depression](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#depression).

batholith

A very large body of igneous rock, usually granite, which has been exposed by erosion of the overlying rock.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

bathymetry

1. The measurement of water depth, mainly of seas and oceans but sometimes of deep lakes.
2. The study and depiction of the physical features or relief of the floor of a lake or ocean. In this sense bathymetry is considered the underwater equivalent of hypsometry or topography.

bay

A coastal body of water that is directly connected to but recessed from a larger body of water, such as an ocean, sea, lake, or another bay. The land surrounding a bay often shelters it from strong winds and waves, making bays ideal places for ports and harbors. Bays are sometimes found adjacent to headlands on discordant coastlines.

beach

A landform along the shoreline of an ocean, sea, lake, or river with a loose surface of sand, gravel, shingle, pebbles, shells, stones, or coral.

bearing

The direction or position of an object, or the direction of an object's movement, relative to a fixed point. It is typically measured in degrees and can be determined with a compass. By convention, magnetic north is defined as having a bearing of zero degrees.

bedrock

The solid rock in the Earth's crust that underlies all soil and other loose material; the rock material that breaks down eventually to form soil.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

bight

A bend or curve in a coastline, river, or other geographical feature typically indicating an especially large, open bay that is shallower than a sound.

biological diversity

Also called biodiversity.

A concept recognizing the variety of life forms in an area of the Earth and the ecological interdependence of these life forms.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

biogeography

The study of the distribution of biological species and ecosystems in geographic space and through geological time.

biosphere

The realm of all living things.[[3]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-USGS_2010-3)

biota

The animal and plant life of a region considered as a total ecological entity.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

blowout

A sandy depression formed when wind erodes into patches of bare sand on otherwise vegetation-stabilized sand dunes at the margins of coastal and arid ecosystems.

bocage

A landscape of mixed woodland and pasture, with fields and winding country lanes sunken between low, narrow ridges and banks surmounted by tall, thick hedgerows, especially as found in rural parts of western Europe.

body of water

Any significant accumulation of water, either natural or artificial, on the surface of the Earth. Bodies of water may hold or contain water, as with lakes and oceans, or they may collect and move water from one place to another, as with rivers, streams, and other watercourses.

bog

Also called a mire, quagmire, or [muskeg](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#muskeg).

A type of wetland which accumulates deposits of dead plant material, especially mosses, known as peat. Bogs occur where the water at the ground surface is acidic and low in dissolved nutrients. They are one of four main types of wetland.

bootheel

See [salient](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#salient).

border

The geographical boundary of a political entity or legal jurisdiction, such as a country, state, or other subnational entity.[[1]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-OERI_1996-1)

bornhardt

A bald, steep-sided, dome-shaped hill, mountain, or rock outcropping at least 30 metres (98 ft) in height and several hundred meters in width. Compare [inselberg](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#inselberg), [tor](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#tor), and [nubbin](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#nubbin).

borough

A type of administrative subdivision in certain English-speaking parts of the world. Though traditionally used to refer to a fortress or a walled town, modern usage of the term can variably refer to any town with its own local self-government, a formal or informal subdivision of a large metropolis (as in New York City and London), or an entire administrative region (as in the U.S. state of Alaska).

box canyon

A short, narrow canyon with steep walls on three sides, allowing entry and exit only through the mouth of the canyon.

break-in-bulk point

A transfer point on a transport route where the mode of transport or type of carrier changes and where large-volume shipments are reduced in size. For example, goods may be unloaded from a ship and transferred to trucks at an ocean port.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

breakwater

Any man-made structure built on the coast of a body of water, typically the sea, in order to reduce the intensity of wave action in an area adjacent to the shore, thereby providing safe harbourage for human activities in the inshore waters. Breakwaters may also be designed to protect the coastline from coastal erosion and longshore drift.

built environment

The human-made spaces that provide the setting for human activity, in which people live, work, and recreate on a day-to-day basis.

butte

An isolated hill or mountain with steep or precipitous sides, usually having a smaller summit area than a mesa.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

cadastre

Also spelled cadaster.

A type of parcel-based land recording system containing a comprehensive record of interests in individual units of land within a country or other polity, usually including a geometric description of each parcel's physical location, dimensions, and boundaries that is linked to legal information detailing the nature of the interests (e.g. rights, restrictions, and responsibilities), the ownership or control of those interests, and the economic value of the land and its improvements. The cadastre is a fundamental source of data used in resolving disputes between landowners.

calanque

A narrow, steep-sided valley surrounding an inlet formed in karstic regions along the Mediterranean coast, either by fluvial erosion or the collapse of the roof of a cave that has been subsequently partially submerged by a rise in sea level.

caldera

A large, cauldron-shaped depression that forms through the subsidence and collapse of a ground surface following the evacuation of an underlying magma chamber.

canal

A navigable artificial water channel, usually built as a conduit for human activity.

canyon

Also called a gorge or spelled cañon.

A deep cleft between cliffs or escarpments, or a rift between two mountain peaks, resulting from weathering and the erosive activity of a river over long periods of geologic time.

cape

A large headland or promontory extending into a body of water, usually a sea or ocean.

caprock

A stratum of erosion-resistant sedimentary rock (usually limestone) found in arid areas. Caprock forms the top layer of most mesas and buttes.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

cardinal directions

The set of four primary directions used in cartography and navigation: north (N), south (S), east (E), and west (W). Together they form the primary divisions of the compass rose. They can be further subdivided into the intercardinal directions and secondary-intercardinal directions.

carrying capacity

The total number of human beings that an area can support given the quality of the natural environment and the level of technology of the population.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

cartography

The study and practice of making maps and charts. A person who draws or makes maps or charts is called a cartographer.[[1]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-OERI_1996-1)

cartogram

A map in which some thematic mapping variable, such as travel time, population, or gross national product, is substituted for traditional measures of land area or distance such that the geometry or space of the map is distorted in order to convey and emphasize the information of the alternate variable.

cave

Any naturally hollow underground space large enough for a person to enter.

cavern

A type of solutional cave that is formed in soluble rock with the ability to grow speleothems.

cay

A small, sandy, low-elevation island on the surface of an otherwise submerged coral reef; a type of coral island. Compare [atoll](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#atoll).

celestial pole

Either of the two imaginary points in the sky at which an indefinitely extended projection of the Earth's axis of rotation intersects the celestial sphere. As the Earth rotates upon its axis, the north and south celestial poles remain permanently fixed in the sky (directly overhead to observers at the North Pole and South Pole, respectively), and all other points appear to rotate around them.

cenote

A natural pit or sinkhole resulting from the collapse of limestone bedrock which exposes groundwater underneath.

central business district

A centrally located commercial business district in an urban area, typically containing a concentration of office and retail activities.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

census-designated place (CDP)

A concentration of population identified by the United States Census Bureau for statistical purposes.

channel

Also called a strait.

1. A waterway separating two relatively close landmasses.
2. Any narrow body of water that connects two larger bodies of water.
3. The deepest part of a shallow body of water, often used as a passageway for large ships.

chaparral

A class of terrestrial vegetation characterized by dense, impenetrable thickets of shrubs or dwarf trees.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

chimney

See [salient](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#salient).

chine

A steep-sided coastal gorge, typically of soft eroding cliffs of sandstone or clay, through which a river or stream flows to the sea. The term is used primarily in Southern England.

chinook

A warm, dry wind experienced along the eastern side of the Rocky Mountains in the United States and Canada. Most common in winter and spring, it can result in a rise in temperature of 20 °C (68 °F) in a quarter of an hour.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

chorography

The art of establishing, describing, or mapping a geographic region or district, or more broadly, the representation of space or place.

choropleth

A map showing the distribution of a phenomenon by graded shading which indicates the density per unit area of that phenomenon; the darker the shading, the greater the density.[[4]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-Mayhew-4)

cinder cone

A steep-sided volcano formed by the explosive eruption of cinders that form around a vent. Cinders are lava fragments about 1 centimetre (0.39 in) in diameter.[[3]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-USGS_2010-3)

circle of latitude

See [latitude](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#latitude).

cirque

Also called a corrie or cwm.

An amphitheatre-shaped valley surrounded on three or more sides by steep, cliff-like slopes and formed by glacial or fluvial erosion.

city

A large human settlement, generally with extensive systems constructed for housing, transportation, sanitation, utilities, and communication.

city-state

A sovereign state or small independent country that usually consists of a single city and its dependent territories.

cliff

Any vertical or nearly vertical rock exposure, usually formed by the processes of weathering and erosion.

climax vegetation

The vegetation that would exist in an area if growth had proceeded undisturbed for an extended period. This would be the "final" collection of plant types that presumably would remain forever, or until the stable conditions were somehow disturbed.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

coast

Also called a coastline or seashore.

The area where land meets a sea or ocean. Coastal zones are regions where the interaction of terrestrial and marine processes occurs. Compare [shore](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#shore).

col

Also called a gap or notch.

The lowest point on a mountain ridge between two peaks.

colony

A territory under the immediate complete political control of a sovereign metropolitan state but otherwise distinct, often geographically, from the state's home territory. Colonies have no international representation independent of the metropolitan state. Compare [satellite state](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#satellite_state).

compass

An instrument used for navigation and orientation that indicates direction relative to the geographic cardinal directions by measuring the orientation of the Earth's magnetic field with respect to the North Magnetic Pole. Compasses often display markings for angles or degrees, which allow them to show azimuths and bearings, in addition to a compass rose.

compass rose

A figure on a compass, map, nautical chart, or monument used to display the orientation of the four cardinal directions — North, East, South, and West — and their intermediate points.

confluence

The place at which two or more rivers or other watercourses flow together to form one larger river or watercourse.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

coniferous

Bearing cones; from the conifer family.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

contiguity

The characteristic of a group of neighboring political or geographical divisions not being interrupted by politically unaffiliated land or water. Such divisions are said to be contiguous.

continent

One of several very large, contiguous landmasses into which the Earth's land area is divided, generally by geographical or political convention rather than any strict criteria.[[1]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-OERI_1996-1) Geologically, continents correspond largely to areas of continental crust on continental plates.

continental climate

The type of climate found in the interior of the major continents in the middle, or temperate, latitudes. The climate is characterized by a great seasonal variation in temperatures, four distinct seasons, and a relatively small annual precipitation.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

continental divide

The line of high ground that separates the different oceanic drainage basins of a particular continent. The river systems of a continent on opposite sides of a continental divide flow toward different oceans. See [drainage divide](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#drainage_divide).[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

continental shelf

A portion of a continent that is submerged beneath an area of relatively shallow water known as a shelf sea. Though continental shelves are usually treated as physiographic provinces of the ocean, they are not part of the deep ocean basin proper but the flooded margins of the continent.

continentality

The quality of being located on a continent.

contour lines

Lines marked on topographic maps which show the shape and elevation of the land by connecting points of equal elevation.[[3]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-USGS_2010-3)

conurbation

An extensive urban area formed when two or more initially separate cities coalesce to form a continuous metropolitan area.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

core area

The portion of a country that contains its economic, political, intellectual, and cultural focus. It is often the center of creativity and change. See [hearth](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#hearth).[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

corrasion

The process of mechanical erosion of the Earth's surface by the impact or grinding action of particles being transported across it, either by moving water, waves, glaciers, wind or gravity.

corrie loch

See [tarn](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#tarn).

coulee

A dry canyon eroded by Pleistocene floods that cut into the lava beds of the Columbia Plateau in the western United States.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

couloir

A narrow gully with a steep gradient in a mountainous terrain, often enclosed by sheer cliffs and filled with snow or ice even during the summer months.

country

A region identified as a distinct national entity in political geography. Compare [state](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#state).

county

A type of subnational division of a country or federal state used for administrative or other purposes.

crater

Any large, roughly circular depression, pit, or hole in the Earth's surface. Craters can be classified into different types based on their ultimate causes; see [impact crater](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#impact_crater), [volcanic crater](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#volcanic_crater), and [pit crater](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#pit_crater).[[3]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-USGS_2010-3)

crater lake

A lake that forms in a volcanic crater or caldera (such as a maar), an impact crater left by a meteorite, or a crater resulting from a man-made explosion.

crust

The thin shell of solid material that is the Earth's outermost layer and the outermost component of the lithosphere. The Earth's crust is generally divided into two distinct types, oceanic crust and continental crust, both of which "float" on top of the mantle.[[3]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-USGS_2010-3)

cryosphere

The totality of water in the solid phase on the Earth's surface, including glaciers; sea, lake, and river ice; snow; and permafrost. The cryosphere is sometimes considered a subset of the hydrosphere.[[3]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-USGS_2010-3)

cryoturbation

Also called frost churning.

The mixing of materials from various horizons of the soil down to the bedrock due to freezing and thawing.

cuesta

A long, low ridge with a steep scarp slope and a gentle backslope (dip slope).

cultural geography

A branch of human geography which studies the patterns and interactions of human culture in relation to the natural environment and the human organization of space.

culture

The accumulated habits, attitudes, and beliefs of a group of people that define for them their general behavior and way of life; the total set of learned activities of a people.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

culture hearth

The area from which the culture of a group diffused. See [hearth](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#hearth).[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

cut bank

A continually eroding bank along a meandering river or stream channel, especially a bank that has been eroded into a nearly vertical cliff. Cut banks generally form on the outside bend of a deep meander, opposite the depositional point bar that forms on the inside bend.

cwm

See [cirque](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cirque).

Cyclopean stairs

A term referring to the longitudinal profile of some glaciated valleys which have been eroded into a series of consecutive hanging valleys resembling stairs.

dale

Another name for a valley.

dam

Any barrier, either natural or artificial, that stops or restricts the flow of water, either on the surface or underground. Man-made dams are most commonly built to impound rivers or streams, generally to retain water for purposes such as human consumption, irrigation, aquaculture, or power generation (whereas related structures such as floodgates and levees are more specifically designed to manage or prevent water flow into particular areas).

de facto segregation

The spatial and social separation of populations that occurs without legal sanction.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

de jure segregation

The spatial and social separation of populations that occurs because of legal measures.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

debouch

Also spelled debouche.

A place where water runoff from a relatively small, confined space emerges into a much larger, broader space, or where a body of water pours forth from a narrow opening, such as where a stream or river enters a lake or ocean.

deciduous forest

A forest composed of trees which lose their leaves each year.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

defile

A narrow pass or gorge between mountains or hills.

degree

A unit of angular measure. A circle is divided into 360 degrees, represented by the º symbol. Degrees are used to divide the roughly spherical shape of the Earth for geographic and cartographic purposes.[[1]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-OERI_1996-1)

degree day

Deviation of one-degree temperature for one day from an arbitrary standard, usually the long-term average temperature for a place.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

dell

A small, secluded hollow, usually within a grassy, park-like, partially wooded valley.

delta

A landform at the mouth of a river where the main stem splits up into several distributaries. It is formed from the deposition of the sediment carried by the river as the flow leaves the mouth of the river. Compare [estuary](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#estuary).[[5]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-NRCS_2018-5)

demography

The systematic analysis of population.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

depression

Any landform that is sunken or depressed below the surrounding area. Depressions include an enormous variety of landforms and can form by a number of different mechanisms, including erosion, ground collapse, tectonic activity, volcanism, and meteorite impacts.

desert

An arid, barren area of land where little precipitation occurs and living conditions are consequently unfavorable for most plant and animal life. Deserts are characterized by exposure of the unprotected ground surface to processes of denudation as well as large variations in temperature between night and day. They are often classified by the amount of precipitation they receive, by their average temperature, by the causes of their desertification, or by their geographical location.

digital elevation model (DEM)

A three-dimensional computer graphics representation of a geographic terrain surface created from elevation data. DEMs are the most common basis for digitally produced relief maps.

dike

See [levee](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#levee).

distance decay

The decrease in cultural or spatial interactions between two places as the distance between them increases. This effect may be noticeable in towns and cities, where certain descriptive characteristics such as pedestrian traffic, building height, and land value tend to decline with greater distance from the city center.

distributary

A stream or river that branches off and flows away from a main channel. Distributaries are common near river deltas. Contrast [tributary](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#tributary).

dome

1. A steep-sided mound that forms when very viscous lava is extruded from a volcanic vent.[[3]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-USGS_2010-3)
2. An uplifted area of sedimentary rock with a downward dip in all directions, often caused by molten rock material pushing upward from below. The sediments have often eroded away, exposing the rocks that resulted when the molten material cooled.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

dormant volcano

An active volcano that is in repose (quiescence) but is expected to erupt in the future.[[3]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-USGS_2010-3)

drift ice

Also called brash ice.

A type of sea ice consisting of multiple ice floes that are not attached to the shoreline or any other fixed object such as a shoal, and which are therefore free to "drift" under the influence of winds and ocean currents. Contrast [fast ice](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#fast_ice).

drainage basin

Also called a catchment area, drainage area, river basin, water basin, or watershed.

Any area of land where precipitation collects and drains into a common outlet, such as a river, lake, ocean, or any other body of water. The drainage basin includes all of the surface water from precipitation runoff and snowmelt, as well as all of the groundwater beneath the Earth's surface. Each drainage basin is separated topographically from adjacent basins by a drainage divide.

drainage divide

Also called a water divide, ridgeline, watershed, or water parting.

The topographical barrier that separates neighboring drainage basins. Divides are often, though not always, located along conspicuous elevated ridges or mountain ranges.

draw

Also called a re-entrant.

A terrain feature formed by two parallel ridges or spurs with low ground in between them.

drumlin

An elongated hill in the shape of an inverted spoon or half-buried egg which is formed by glacial ice acting on underlying unconsolidated till or ground moraine.

dry farming

A type of farming practiced in semi-arid or dry grassland areas without irrigation using such approaches as fallowing, maintaining a finely broken surface, and growing drought-tolerant crops.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

dry point

An area of firm or dry ground in a wetland, marsh, or floodplain, often capable of supporting a human settlement.

dune

A hill of loose sand built by the movements and erosional and depositional processes of wind or water, often occurring in deserts and coastal areas.

Earth science

Also called the Earth sciences or geoscience.

1. A collective term for the various fields of natural science related to the planet Earth.
2. The branch of science that studies the physical constitution and characteristics of the Earth and its atmosphere, using methods and tools from geography, geology, physics, chemistry, biology, and mathematics to build a quantitative understanding of how the Earth works and changes over time.

earthquake

The sudden and intense shaking of the ground due to tectonic activity.

Eastern Hemisphere

The half sphere of the Earth that is east of the Prime Meridian and west of the antimeridian. It is opposite the Western Hemisphere.

economic geography

A sub-discipline of geography which studies the location, distribution, and spatial organization of economic activities across the world.

economies of agglomeration

The economic advantages that accrue to an activity by locating close to other activities; benefits that follow from complementarity or shared public services.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

ecoregion

Also called an ecological region.

A type of biogeographic province that is smaller than a bioregion and which contains characteristic, ecologically and geographically distinct, and relatively uniform assemblages of biological communities and species. Ecoregion boundaries often overlap within ecotones and mosaic habitats, and most ecoregions contain habitats that differ from those described for their assigned biome.

edge city

A concentration of businesses, commercial buildings, or retail and entertainment venues situated outside of a traditional downtown or central business district in what was previously a suburban residential or rural area.

edgelands

The transitional areas of "fringe" space at the boundaries of a country, city, or other artificial geographical entity, often distinguished by a partly man-made, partly natural landscape that is in the earliest stages of human management and organization. Compare [hinterland](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#hinterland).

ekistics

The scientific study of human settlements of all types, incorporating concepts such as regional, metropolitan, and community planning and dwelling design with the goal of achieving harmony between the inhabitants of a settlement and their physical, social, and cultural environments.

elevation

The height of a point on the Earth's surface with respect to sea level. Compare [altitude](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#altitude).[[1]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-OERI_1996-1)

emergent coastline

A coast or shoreline resulting from a rise in land surface elevation relative to sea level.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

enclave

A tract or territory completely surrounded by and enclosed within the territory of one other state, country, or other political entity. Unlike enclaves, exclaves can be surrounded by more than one other state.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

endorheic basin

A closed drainage basin that allows little or no outflow to external bodies of water but converges instead into internal lakes or swamps which equilibrate through evaporation.

epicenter

The point on the Earth's surface directly above the focus of an earthquake, near which the seismic waves produced by the earthquake are usually most noticeable.

Equator

The imaginary circle around the Earth halfway between the geographic poles which is assigned a latitude of zero degrees and is therefore used as a reference point for all other lines of latitude. It is the largest circumference of the Earth.[[1]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-OERI_1996-1)

erratic

A boulder that has been carried from its source by a glacier and deposited as the glacier melted. Such boulders are often of different rock types than the surrounding rocks.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

escarpment

A long cliff or steep slope separating two comparatively level or more gently sloping surfaces and resulting from erosion or faulting.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

esker

Also called an os or spelled eskar or eschar.

A long, winding ridge of stratified sand and gravel, usually occurring in glaciated or formerly glaciated areas.

estuary

The broad lower course of a river where it enters the ocean and is affected by the tides. Compare [delta](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#delta).[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

etchplain

A plain beneath which the bedrock has been subjected to considerable subsurface weathering, known as "etching". Erosion of the regolith overlying an etchplain often exposes topographical irregularities such as inselbergs.

evapotranspiration

The process by which water is lost from an area through the combined effects of evaporation from the ground surface and transpiration from vegetation.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

evorsion

See [pothole](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#pothole).

exclave

A portion of a state or territory that is geographically separated from the main part by surrounding foreign territory of one or more other states or political entities. Many exclaves are also enclaves.

exotic stream

A stream found in an area that is too dry to have spawned such a flow. The flow originates in some moister section.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

extinct volcano

A volcano that is not expected to erupt again.[[3]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-USGS_2010-3)

exurban

An adjective describing a region or district that lies outside a city and usually beyond its suburbs; a place of this type is called an exurb. Compare [rural](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#rural).[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

fall line

A geomorphologic unconformity between an upland region of relatively hard crystalline basement rock and a coastal plain of softer sedimentary rock.

fallow

Agricultural land that is plowed or tilled but left unseeded during a growing season. Fallowing is usually done to conserve moisture.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

fault

A fracture in the Earth's crust accompanied by a displacement of one side of the fracture.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

fault-block mountain

A mountain mass created by either the uplift of land between faults or the subsidence of land outside the faults.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

fault zone

An area of numerous fractures in the Earth's crust along which movement has occurred. The movement may be in any direction and involve material on either or both sides of the fractures.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

federation

A form of government in which powers and functions are divided between a central government and a number of political subdivisions that have a significant degree of political autonomy.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

field

Also called a spatially dependent variable.

A quantity that can be theoretically assigned to any point of space, such as temperature, soil moisture, or population density. Both scalar and vector fields are found in geographic applications, although the former is more common.

figure of the Earth

The size and shape of the Earth as studied in geodesy. Applications requiring varying levels of precision have led to the development of many different models of the Earth, ranging from simple spheres to much more accurate approximations such as geoids.

firn

A type of ice that is at an intermediate stage between snow and glacial ice. More specifically, firn is partially compacted névé left over from past seasons which has subsequently recrystallized into a form that is harder and denser than névé.

firth

Another name for a coastal inlet, strait or bay associated with the mouth of a large river, where the tidal effects of seawater passing upriver have widened the riverbed into an estuary. The term is used primarily in Scotland.

fish ladder

A series of shallow steps down which water is allowed to flow, designed to permit salmon to circumvent artificial barriers such as dams as they swim upstream to spawn.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

fissure

A long, narrow opening or line of breakage made by cracking or splitting, especially in rock or earth.[[2]](https://en.wikipedia.org/wiki/Glossary_of_geography_terms#cite_note-IIP_2008-2)

fjord

Also spelled fiord.

A long, narrow marine inlet with steep sides or cliffs created by glacial erosion.

floodplain

A broad, flat area of land adjacent to a river or stream which is leveled by annual flooding and by the lateral and downstream movement of meanders.

focality

The characteristic of a place that follows from its interconnections with more than one other place. When interaction within a region comes together at a single place (i.e., when the movement focuses on that location), the place is said to possess focality.

focus

Also called the hypocenter.

The point inside the Earth's crust from which an earthquake originates.

foothills

A geographic transition zone defined by gradual increases in elevation between plains or low-relief hills and adjacent topographically higher hills, mountains, or uplands.

forest

Any extensive area dominated by communities of trees.

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