Geographical Terms : Glossary
Igneous rock: Rock formed when molten (melted) materials harden.
Indigo: A plant that yields a blue vat dye.
Insular: Either of an island, or suggestive of the isolated condition of an island.
International Date Line: A line of longitude generally 180 degrees east and west of the prime meridian. The date is one day earlier to the east of the line.
Island: Any piece of sub-continental land that is surrounded by water.
Isohyet: A line on a map connecting points that receive equal precipitation.
Jurisdiction: The right and power to apply the law; the territorial range of hills between mountains.
Jhum cultivation: Also called “slash-and-burn” or “jhoom cultivation”; clear-cutting and/or setting fire to an area of land so it can be used for farm cultivation.
Karst: An area possessing surface topography resulting from the underground solution of subsurface limestone or dolomite.
Kudzu: A vine, native to China and Japan but imported into the United States; originally planted for decoration, for forage, or as a ground cover to control erosion. It now grows wild in many parts of the southeastern United States.
Lava: The term used for magma once it has erupted onto the Earth’s surface.
Latitude: A measure of distance north or south of the equator. One degree of latitude equals approximately 110 kilometers (68 mi). Imaginary lines that cross the surface of the Earth parallel to the Equator, measuring how far north or south of the Equator a place is located.
Lateral blast: A sideways-directed explosion from the side or summit of a volcano.
Lacustrine plain: A nearly level land area that was formed as a lakebed.
Leaching: A process of soil nutrient removal through the erosive movement and chemical action of water.
Leeward: The side of a land mass sheltered from the wind—the opposite of windward.
Legume: A plant, such as the soybean, that bears nitrogen-fixing bacteria on its roots, and thereby increases soil nitrogen content.
Lignite: A low-grade brownish coal of relatively poor heat-generating capacity.
Lithosphere: The Earth’s hard, outermost shell. It comprises the crust and the upper part of the mantle. It is divided into a mosaic of 16 major slabs, or plates.
Loess: A soil made up of small particles that were transported by the wind to their present location.
Longitude: A measure of distance east and west of a line drawn between the North and South Poles and passing through the Royal Observatory at Greenwich, England.: Imaginary lines that cross the surface of the Earth, running from north to south, measuring how far east or west of the prime meridian a place is located.