The Chinese word "石油" is formed by directly combining the character "石" (shí), meaning "stone" or "rock", with "油" (yóu), meaning "oil". This creates a literal and descriptive term for petroleum, effectively conveying the idea of "stone oil" to denote the natural resource that is extracted from geological rock formations. The combination visually and conceptually links the substance (oil) with its common source or location (within rocks), resulting in a compound that intuitively represents the material.