The geographical name for the part of the earth's surface covered by water is the hydrosphere. It includes oceans, seas, lakes, rivers, and even water vapor in the atmosphere. The hydrosphere plays a crucial role in weather patterns, climate regulation, and supporting ecosystems. Approximately 71% of the Earth's surface is covered by water, which is essential for life. Managing the hydrosphere is vital for sustainability and addressing issues like pollution and water scarcity.