Hydrosphere (Greek hydro- means "water") in physical geography, describes collective mass of water that is found under, on and over the surface of the Earth.

Water comprising hydrosphere is found in various forms :

• under the Earth's surface and in rocks
• in biosphere - plants and animals
• water covering the Earth's surface in liquid and solid forms (ice, snow)
• atmospheric water in clouds and water vapour

Other spheres are :

• lithosphere
• atmosphere