"Yer altı suyu" refers to groundwater, which is water that is found beneath the Earth's surface. It is stored in soil and rock formations known as aquifers. Groundwater is a crucial resource for drinking water, irrigation, and industrial uses, making it essential for both human activities and ecosystems. The movement of yer altı suyu is influenced by various factors, including rainfall, soil composition, and geological formations. It can be accessed through wells and springs. Proper management of groundwater is vital to prevent depletion and contamination, ensuring its availability for future generations.