The Chinese word **水库 (shuǐkù)**, meaning "reservoir" or "dam," is a straightforward compound formed by combining two independent characters: **水 (shuǐ)**, meaning "water," and **库 (kù)**, meaning "warehouse," "storehouse," or "repository." The formation follows a common modifier-noun (or "determinative") structure in Chinese, where the first element **水** specifies the type or content, and the second element **库** indicates the category or function. Thus, the compound logically means a "water storehouse"—a man-made structure designed to store and contain water, perfectly capturing the essence of the modern engineering concept.