• A zone is an area separated from other areas in some artificial or natural manner. Many different types and sizes of zones exist.

    Twenty-four artificially defined time zones help standardize timekeeping worldwide. The time zones are based on the official time in Greenwich, England—called Greenwich Mean Time—and may follow natural or political borders in different parts of the world.

    The world is sometimes divided into five zones according to latitude. The tropical, or Torrid Zone, lies near the Equator and extends to the Tropic of Cancer in the north and the Tropic of Capricorn in the south. The north and south frigid zones (also known as the Arctic and the Antarctic) lie near the poles. In between them lie the north and south temperate zones.

    Altitudinal zones are naturally defined. They arise because temperatures and moisture levels change drastically at different altitudes. As a result, vegetation or certain species of animals can only flourish in their specific zones.

    When two regions are not sharply divided, the area between them becomes a transition zone. The Earth’s geologic transition zone is located in the mantle, beneath the Earth’s crust. The mantle is filled with magma and other elastic solids. The transition zone exists between the lower mantle, close to the Earth’s superheated core, and the upper mantle, where magma can penetrate the Earth’s crust as lava.

    The intertidal zone is a transition zone between the ocean and the beach. Organisms that live there, such as sea grasses and starfish, must be able to tolerate conditions of both zones.

    A fence is the zone between public and private land, above.
  • Term Part of Speech Definition Encyclopedic Entry
    altitudinal zone Noun

    section of landscape between two elevations. Also called an altitudinal band.

    Antarctic Noun

    region at Earth's extreme south, encompassed by the Antarctic Circle.

    Arctic Noun

    region at Earth's extreme north, encompassed by the Arctic Circle.

    Encyclopedic Entry: Arctic
    border Noun

    natural or artificial line separating two pieces of land.

    Encyclopedic Entry: border
    core Noun

    the extremely hot center of Earth, another planet, or a star.

    Encyclopedic Entry: core
    crust Noun

    rocky outermost layer of Earth or other planet.

    Encyclopedic Entry: crust
    Earth Noun

    our planet, the third from the Sun. The Earth is the only place in the known universe that supports life.

    Encyclopedic Entry: Earth
    elastic Adjective

    able to bend easily.

    Equator Noun

    imaginary line around the Earth, another planet, or star running east-west, 0 degrees latitude.

    Encyclopedic Entry: equator
    flourish Verb

    to thrive or be successful.

    geologic Adjective

    having to do with the physical formations of the Earth.

    Greenwich Mean Time Noun

    standard time, calculated by the time at the site of the prime meridian running through Greenwich, England. Also called Zulu Time and Universal Time.

    intertidal zone Noun

    region between the high and low tide of an area.

    latitude Noun

    distance north or south of the Equator, measured in degrees.

    Encyclopedic Entry: latitude
    lava Noun

    molten rock, or magma, that erupts from volcanoes or fissures in the Earth's surface.

    magma Noun

    molten, or partially melted, rock beneath the Earth's surface.

    Encyclopedic Entry: Magma's Role in the Rock Cycle
    mantle Noun

    middle layer of the Earth, made of mostly solid rock.

    Encyclopedic Entry: mantle
    moisture Noun


    pole Noun

    extreme north or south point of the Earth's axis.

    temperate Adjective


    temperature Noun

    degree of hotness or coldness measured by a thermometer with a numerical scale.

    Encyclopedic Entry: temperature
    time zone Noun

    one of Earth's 24 divisions distinct by one hour, roughly 15 degrees of longitude.

    Torrid Zone Noun

    area between the latitudes of the Tropic of Cancer and the Tropic of Capricorn.

    transition zone Noun

    area between two natural or artificial regions.

    vegetation Noun

    all the plant life of a specific place.

    zone Noun

    area separated from others by artificial or natural divisions.

    Encyclopedic Entry: zone