The word 血压 (blood pressure) is formed through a direct, logical combination of its two component characters: 血 (xuè), meaning "blood", and 压 (yā), meaning "pressure". It is a conceptual compound where the first character identifies the substance or medium, and the second character specifies the type of force or action applied to it. Together, they create a new, unified concept that precisely denotes the physiological force exerted by circulating blood upon the walls of blood vessels, effectively picturing "the pressure of the blood".