Geosphere
Considered the solid portions of the earth, including the hydrosphere and the lithosphere, as opposed to the atmosphere, which lies above it. At their conjunction is the biosphere.
Hydrosphere
Considered as the water portion of the earth’s surface. Part of the geosphere.
Lithosphere
The solid, outer portion of the earth’s crust coupled to the rigid upper mantle. Part of the geosphere.
Atmosphere
The gaseous or air portion of the physical environment that encircles a planet. In the case of the earth, it is held more or less near the surface by the earth’s gravitational attraction. The divisions of the atmosphere include the troposphere, the stratosphere, the mesosphere, the ionosphere, and the exosphere.
Biosphere
The transition zone between the earth and the atmosphere within which most terrestrial life forms are found. It is considered the outer portion of the geosphere and the inner or lower portion of the atmosphere.