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.

zone
A fence is the zone between public and private land, above.
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.

Noun

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

Noun

natural or artificial line separating two pieces of land.

Noun

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

Noun

rocky outermost layer of Earth or other planet.

Noun

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

elastic
Adjective

able to bend easily.

Noun

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

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.

Noun

region between the high and low tide of an area.

Noun

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

lava
Noun

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

Noun

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

Noun

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

moisture
Noun

wetness.

pole
Noun

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

temperate
Adjective

moderate.

Noun

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

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.

Noun

area separated from others by artificial or natural divisions.