Geosphere is another term for the lithosphere of the Earth. If one is speaking of a chunk of stuff floating around in space other than the Earth itself, "lithosphere" would be more correct because it comes from "lithos" meaning "rock" (instead of "geos" which means "Earth"). The normal context in which one sees this word is when talking about the various conceptual pieces of "planet-like things" as related to the carbon cycle. The other pieces are hydrosphere, atmosphere, and biosphere.
