geology

noun

ge·​ol·​o·​gy jē-ˈä-lə-jē 

plural geologies

1

a

: a science that deals with the history of the earth and its life especially as recorded in rocks

b

: a study of the solid matter of a celestial body (such as the moon)

2

: geologic features

the geology of Arizona

3

: a treatise on geology

geologist

jē-ˈä-lə-jist 

noun

Examples of geology in a Sentence

learning about the geology of Hawaii

Recent Examples on the Web

Mars is famous for its volcanoes, canyons and ancient river valleys, but some of its most active geology happens in slow motion, powered by air. —Kenna Hughes-Castleberry, Space.com, 20 Jan. 2026

The mining challenge is not just geology. —Güney Yıldız, Forbes.com, 19 Jan. 2026

During the high season, the train even has an onboard national park guide who shares information about the geology and history of the areas the train passes. —Evie Carrick, Travel + Leisure, 18 Jan. 2026

Radon is a serious public health issue in Minnesota due to the state’s geology and cold climate, according to MDH. —Mars King, Twin Cities, 17 Jan. 2026

Word History

Etymology

New Latin geologia, from ge- + -logia -logy

First Known Use

1735, in the meaning defined at sense 1a

Rhymes for geology

• anthology
• apology
• astrology
• biology
• christology
• chronology
• conchology
• cosmology
• cryptology
• cytology
• doxology
• ecology

Kids Definition

geology

noun

ge·​ol·​o·​gy jē-ˈäl-ə-jē 

plural geologies

1

a

: a science that deals with the history of the earth and its life especially as recorded in rocks

b

: a study of the features of a heavenly body (as the moon)

2

: the geologic features (as mountains or plains) of an area

geologic

ˌjē-ə-ˈläj-ik

adjective

or geological

-i-kəl

geologically

-i-k(ə-)lē

adverb

geologist

jē-ˈäl-ə-jəst 

noun