The water cycle, also known as the hydrological cycle, is the continuous process by which water is circulated throughout the Earth and its atmosphere. It involves the evaporation of water from bodies of water, such as oceans and lakes, the condensation of water vapor into clouds, precipitation in the form of rain, snow, sleet, or hail, and the runoff of water back into bodies of water. This cycle plays a crucial role in maintaining the Earth's ecosystem and providing fresh water for various organisms.