The oceans are the largest source of water for the hydrological cycle, accounting for approximately 97% of the Earth's total water.

Condensation is the process by which water vapor in the atmosphere cools and changes into a liquid or solid state.

Evaporation is the process by which water changes from a liquid to a gaseous state, transferring water from the Earth's surface to the atmosphere.

Transpiration is the process by which plants release water vapor into the atmosphere through their leaves.

Aquifer storage refers to the total volume of water contained within an aquifer.

Aquifer discharge refers to the process by which water exits an aquifer, typically through springs, wells, or seepage into surface water bodies.

Aquifer permeability refers to the ability of an aquifer to transmit water, which is influenced by the size and connectivity of pore spaces within the aquifer material.

Aquifer recharge refers to the process by which water is added to an aquifer, typically through infiltration from precipitation, surface water bodies, or other sources.

The unsaturated zone is the region of soil or rock above the water table where the pore spaces are not completely filled with water.

The saturated zone is the region of soil or rock below the water table where the pore spaces are completely filled with water.

The capillary fringe is the transition zone between the unsaturated and saturated zones where water is held by capillary forces above the water table.

Groundwater refers to the water that is stored underground in aquifers.

A well is a structure that is used to extract groundwater from an aquifer.

A spring is a natural opening in the Earth's surface through which groundwater discharges.

Hydrology is the study of the distribution and movement of water on and below the Earth's surface.