ge·ol·o·gy (jē-ŏl'ə-jē)
n., pl., -gies.

1. The scientific study of the origin, history, and structure of the earth.
2. The structure of a specific region of the earth's crust.
3. A book on geology.
4. The scientific study of the origin, history, and structure of the solid matter of a celestial body.

[Medieval Latin geōlogia, study of earthly things : Greek geō-, geo- + Greek -logiā, -logy.]

geologic ge'o·log'ic (jē'ə-lŏj'ĭk) or ge'o·log'i·cal adj.
geologically ge'o·log'i·cal·ly adv.
geologist ge·ol'o·gist n.

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The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.

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