水源 (shuǐ yuán) literally combines 水 (shuǐ), meaning 'water', and 源 (yuán), meaning 'source' or 'origin'. Together, they refer to the natural or artificial origin from which water flows—such as a spring, river headwater, glacier melt, reservoir, or well. It emphasizes where usable water begins its journey into human systems or ecosystems.

This term is commonly used in environmental science, urban planning, public health, and geography. It appears in discussions about water safety ('protected water source'), pollution control ('contaminated water source'), infrastructure ('municipal water source'), and conservation ('preserving mountain water sources'). Unlike more casual terms like 水 (shuǐ) or 井 (jǐng, 'well'), 水源 carries a formal, technical nuance and often implies sustainability, accessibility, and quality.