geo-

¹

1. a combining form meaning “the earth,” used in the formation of compound words:

   geochemistry.

Geo.

²

abbreviation for

1. George.

geo

¹

/ ˈdʒiːəʊ /

noun

1. (esp in Shetland) a small fjord or gully

geo-

²

combining_form

1. indicating earth

   geomorphology

geo–

1. A prefix that means “earth,” as in geochemistry, the study of the Earth's chemistry.

Word History and Origins

Origin of geo-¹

< Greek geō-, combining form of gê the earth

Word History and Origins

Origin of geo-¹

C18: from Old Norse gjā ravine; related to Old English gionian to yawn

Origin of geo-²

from Greek, from gē earth

Example Sentences

In addition to Arnold, the team included University of Minnesota Department of Civil, Environmental, and Geo- Engineering retired adjunct associate professor Paul Capel, former research assistant Grant Goedjen, and John Barry from the DNR's Division of Ecological and Water Resources.

From Science Daily

"Oftentimes people think a natural spring has water that is safe to drink," said Bill Arnold, Distinguished McKnight University Professor & Joseph T. and Rose S. Ling Professor in the University of Minnesota's Department of Civil, Environmental, and Geo- Engineering.

From Science Daily

They include publicly traded prison firms GEO Group and CoreCivic.

From BBC

Check out what happens when milk, food coloring, and dish soap create a cool chemical reaction with this experiment from the Nat Geo Kids book Try This!

From National Geographic Kids

The experiment comes from pages of the Nat Geo Kids book Try This!

From National Geographic Kids

Words That Use geo-

What does geo- mean?

Geo- is a combining form used like a prefix meaning “earth.” It is often used in scientific terms in a variety of fields. In some rare instances, such as the term geocode, geo- is used as an abbreviation of geographical.

Geo- comes from Greek gê, meaning “earth.” A synonym of gê is khthṓn, which is the source of several words related to the underworld, such as chthonic.

What are variants of geo-?

When combined with words or word elements that begin with a vowel, geo- becomes ge-, as in geanticline. Want to know more? Read our Words That Use article for ge-.

Examples of geo-

An example of a word you have likely encountered that features geo- is geology, “the science that deals with the dynamics and physical history of the earth.”

We know geo- means “earth,” so the -logy portion of the word? That’s right, -logy refers to “study,” from the Greek logía. Geology literally translates to “study of the earth.”

What are some words that use the combining form geo-?

• geobotany
• geocarpy
• geocline
• geocentric
• geochemistry
• geochronology
• geochronometry
• geodesic dome
• geodesic line
• geodesy (using the equivalent form of geo- in Greek)
• geodynamics
• geognosy (using the equivalent form of geo- in French)
• geographical (using the equivalent form of geo- in Greek)
• geography (using the equivalent form of geo- in Greek)
• geohydrology
• geological timescale
• geologist
• geomagnetic
• geometry (using the equivalent form of geo- in Greek)
• geomorphic
• geonavigation
• geophone
• geophysics
• geophyte
• geopolitical
• georama
• geoscience
• geoscientist
• geosphere
• geosyncline
• geotag
• geotaxis
• geotectonic
• geotherm
• geothermal
• geothermal energy
• geotropism

What are some other forms that geo- may be commonly confused with?

• gero-
• geront-
• geronto-

Not every word that begins with the exact letters ge-, such as gearbox or geoduck, is necessarily using the combining form ge- to denote “earth.” Learn why geoduck is the name of a kind of saltwater clam at our entry for the word.

Break it down!

Given the meaning of geo-, what is another name for the discipline known as geoscience?