geode ge·ode (jē'ōd')
A cystlike space with or without an epithelial lining, usually observed in subarticular bone in arthritic disorders.
|geode (jē'ōd') Pronunciation Key
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.