雨水 (yǔ shuǐ) literally combines 雨 (yǔ), meaning 'rain', and 水 (shuǐ), meaning 'water', to form the compound noun 'rainwater' — water that has fallen from the sky as rain. It refers specifically to precipitation collected before it mixes with ground contaminants or undergoes human treatment.

This word is commonly used in environmental, agricultural, and ecological contexts — for example, when discussing sustainable water harvesting, plant irrigation, or natural hydrological cycles. Unlike 自来水 (zìláishuǐ, 'tap water') or 矿泉水 (kuàngquán shuǐ, 'mineral water'), 雨水 carries a neutral-to-positive connotation of purity and natural origin, especially in traditional Chinese medicine or farming practices where it’s valued for its softness and lack of minerals.