凉水 literally means 'cool water' — combining 凉 (liáng), meaning 'cool' or 'chilled', and 水 (shuǐ), meaning 'water'. It refers specifically to plain water that is at room temperature or slightly cool, not icy cold (which would be 冰水) nor warm (which would be 温水). Unlike tap water in many Western countries, cool water in China is commonly consumed throughout the day, especially in summer or after physical activity.

This term emphasizes temperature and neutrality: it’s not flavored, carbonated, or heated. It often appears in health-related contexts — traditional Chinese medicine recommends drinking cool (but not icy) water to balance body heat — and in everyday situations like ordering drinks, preparing food, or describing what’s available to drink at home or work.