geo-, ge- +

1. A figure resembling the shape of the Earth: The students in Mrs. Tree's class made a geoid, a perfect representation of the globe.
2. A slightly flattened sphere which is in the shape of the Earth: A geoid is used in calculating the precise measurements of points on the Earth's surface.
3. The theoretical surface that a planet-wide ocean would take if there were no tides or currents: A geoid, or a hypothetical surface of the Earth, would exist if a cross section were taken at sea level, or the figure of the Earth considered as a sea-level surface extended continuously over the entire Earth's surface.

An underground isotherm, or a line drawn on a weather map that connects places with the same temperature: A geoisotherm is a long thin mark connecting points of equal or constant temperatures on the surface of the Earth.

Rare, the worship of the Earth; Earth worship: It seemed that Jane idolised and had great respect for the world and all the things of the Earth, which her parents told her was termed geolatry, a kind of religion.

The relative degree of certainty with which the existence, abundance, and quantity of a given resource can be determined: Many people think that coal or oil have the potential of geological assurance if used wisely and frugally, but sun, as a resource, can be used for electricity, for example, and will never run out!

Specifically, the dating of archaeological data in association with a geological deposit or formation: An example of geological chronology is the dating of Pleistocene human remains in the context of glacial advances and retreats.

A catastrophe caused by movements and deformation of the Earth's crust: Geological disasters can be earthquakes, volcanic eruptions, landslides, and tsunamis, for example.

The study of the features of the floors and margins of the oceans; marine geology; submarine geology: Geological oceanography encompasses descriptions of topography, composition of bottom matter, mutual action of sediments and rocks with air and sea water, the results of motion in the mantle on the sea floor, and activity of wave energy in the submarine crust of the Earth.

A dynamic action or event that occurs at the Earth's surface as a result of the application of natural forces resulting from gravity, temperature changes, freezing and thawing, chemical reactions, seismic shaking, and the agencies of wind and moving water, ice and snow: Where and when the force of a geological process exceeds the strength of the Earth's substance, that substance is changed by deformations, translocations, or chemical reactions.

An extensive region that is characterized by a similar geological history, or by particular structural or physiographical features throughout: A geological province can be exemplified by a basin, a delta, or even by a desert.

A mined facility for the disposal of radioactive waste, using waste packages and the natural geological formations as barriers to provide waste isolation: The deep geological repository idea involves the encapsulation of used nuclear fuel in long-term engineered casks which are placed and sealed within excavated rooms in a geological formation at a determined depth of 500 to 1000 meters below the Earth's surface.

A geological repository involves the construction of a vault within a stable, low permeability bedrock using conventional mining techniques. The bedrock and other engineered barriers are supposed to provide ecological safety over an extended time.

The long-term accumulation of a substance; such as, carbon dioxide or radioactive waste, in a natural geologic formation, for example a sedimentary basin, seabed, or underground cavern: Jack and the geologists were exploring the possibilities of having a geological sequestration in the mountains.

A major demonstration of carbon dioxide injection into a saline formation for sequestration is underway at an offshore gas platform in the North Sea near Norway. Results from this project (and others) suggest that such formations will be reliable for long-term geologic sequestration (storage) sites or carbon dioxide reservoirs.

There are numerous natural carbon dioxide reservoirs throughout the Rocky Mountain states of the United States in geologic "domes" and "traps" suggesting these geological storage formations will be excellent for keeping carbon dioxide captured from industrial facilities.

The presence of a mineral or an aggregate of minerals defines the temperature ranges or limits of the minerals which had been formed: A geological thermometer can measure the temperatures in boreholes in order to provide information about the temperature range within which minerals had been formed.

In geology, a system of measuring the history of the Earth by studying the rocks of the Earth's crust: In a geological time scale, new rocks are generally deposited on top of existing material, those lower down are oldest.

The strata of rock are classified according to their age, and a geological time scale corresponding to this can be constructed.

The main divisions (eras) are the Paleozoid, Mesozoic, and Cenozoic. These are further subdivided into periods and epochs.

An arbitrary chronological arrangement of geological events: Normally a geological time scale is represented in the form of a chart, showing the names of various rock layers and indicating the estimated period of each geological unit of geological time.

The period of time from the end of the formation of the Earth as a separate planet to the beginning of written history, as recorded and illustrated by the succession of rocks: Geological time is the period of time that extends from the beginning of the world to the present day.

Geological time refers to an interval of time occupied by the Earth's geologic history, extending from about 3.9 billion years ago (corresponding to the age of the oldest known rocks) to the present day.

In other words, it is the part of the Earth's history that is recorded in rock strata.

The geological time scale is classified in intervals distinguished by characteristic geological and biological features as indicated by the following longest to the shortest durations, eon (one thousand million years), era (divided into several periods), period (unit of geological time during which a system of rocks is formed), and epoch (geologic time that is a subdivision of a period).