Lithosphere (litho is Greek of stone)
The solid, inorganic portion of Earth, comprising the rock of Earth's crust as well as the broken and unconsolidated particles of mineral matter that overlie the solid bedrock. The surface is shaped into an almost infinite variety of landforms, both on the seafloors and on the surfaces of the continents and islands.
Atmosphere (atmo is Greek of air)
The gaseous envelope of air that surrounds Earth. It contains the complex mixture of gases needed to sustain life. Most of this adheres closely to Earth's surface, being densest at sea level and rapidly thinning with increased altitude. It is a very dynamic sphere, kept in almost constant motion by solar energy and Earth's rotation.
Hydrosphere (hydro is Greek for water)
Comprises water in all its forms. The oceans contain the vast majority of the water found on Earth and are the moisture source for most precipitation.
Biosphere (bio is Greek for life)
Encompasses all the parts of Earth where living organisms can exist; in its broadest and loosest sense, the term also includes the vast variety of earthly life forms (properly referred to as biota).