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.