Geo

GEO or Geo may refer to any of the following:

In computational & scientific use:
* GEO (magazine), a popular scientific magazine
* GEO 600, a detector for gravitational radiation
* Global Environment Outlook, an environmental assessment produced by the United Nations
* Geo (microformat), a microformat for marking up WSG84 geographical coordinates in (X)HTML
* Gene Expression Omnibus, a National Center for Biotechnology Information database for gene expression

In commercial use:
* Geo (marketing), a discipline within marketing analysis
* Geo TV, a leading television channel in Pakistan
* Geo (automobile), a defunct brand of entry-level cars produced by General Motors

People:
* Geo. is sometimes an abbreviation of the name George.
* Geo, the composer for the J-pop group Sweetbox
* Geo Bogza, a Romanian poet and essayist.
* Geo Stelar is the main protagonist in Mega Man Star Force.

As a group:
* "Grupo Especial de Operaciones", a division of the Spanish police
* General Education Officer, the basic rank of teachers of the Ministry of Education in Singapore
* Group on Earth Observations, an intergovernmental organization

As a place:
* GEO, the IATA code for Cheddi Jagan International Airport
* Estadio Casas GEO, stadium in Mexicali, Mexico
* Geo or gio, is a creek (inlet) or gulley in the Orkney and Shetland Islands
* The IOC country code and three letter country code for GEO, a Eurasian country.

As a prefix: geo- is taken from the Greek word γη or γαια meaning "earth", usually in the sense of "ground or land". "Geo-" is thus a prefix for many words dealing in some way with the earth, including:
* Geography, the study of the Earth and its features
** Geology, the study of the Earth's structure
** Geopolitics, the analysis of history, geography and social science with respect to international politics
** Geodesy, also known as geodetics, the study of the measurement and representation of the earth

* Geothermal (geology), heat sources from within the Earth
** Geo-exchange, a heating and cooling system

* Geometry, the study of spatial relationships
** Geocentric, a model of the universe that places the earth at its centre
*** Geostationary orbit, a circular orbit directly above the earth's equator
*** Geosynchronous orbit, an orbit that has the same period as the Earth's sidereal rotation

* Geocaching, an outdoor activity that involves using navigational techniques to finds geocaches

* Geocoding or GeoTagging, encoding coordinates in to features, images, web pages and other data records
** Geolocation, the science of determining the real-world location of a website or website visitor