a hollow concretionary or nodular stone often lined with crystals.
the hollow or cavity of this.
any similar formation.

Origin of geode

1670–80; < French géode < Latin geōdēs < Greek geṓdēs earthlike. See geo-, -ode1
Related formsge·od·ic [jee-od-ik] /dʒiˈɒd ɪk/, ge·od·al [jee-ohd-l] /dʒiˈoʊd l/, adjective Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for geode

Historical Examples of geode

  • The geode is a spherical and apparently solid stone, but when broken is found to be hollow and coated with crystals.

    The Smoky God

    Willis George Emerson

  • The geode has a hollow cell within, lined with beautiful crystals of many colors.

  • No date; no place mentioned; we note the suggestion that it was only a geode, which had been upon the ground in the first place.

  • A geode is a hollow shell of stone, usually quartz, lined with crystals pointing toward the center.

    The Chautauquan, Vol. III, March 1883

    The Chautauquan Literary and Scientific Circle

  • Geode, an irregular shaped stone, containing a small cavity.

British Dictionary definitions for geode



a cavity, usually lined with crystals, within a rock mass or nodule
Derived Formsgeodic (dʒɪˈɒdɪk), adjective

Word Origin for geode

C17: from Latin geōdēs a precious stone, from Greek: earthlike; see geo-, -ode 1
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for geode

rounded stone with a hollow center lined with crystals, 1670s, from French géode, from Latin geodes, from Greek geodes "earthy, earth-like," from ge "earth" (Homeric gaia; see Gaia) + -oides, adjective suffix, "characterized by." Perhaps so called in reference to the "earthy" minerals inside.

Online Etymology Dictionary, © 2010 Douglas Harper

geode in Medicine




A cystlike space with or without an epithelial lining, usually observed in subarticular bone in arthritic disorders.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

geode in Science



A small, hollow, usually rounded rock lined on the inside with inward-pointing crystals. Geodes form when mineral-rich water entering a cavity in a rock undergoes a sudden change in pressure or temperature, causing crystals to form from the solution and line the cavity's walls.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.