The word 适用 is formed by combining two characters, each contributing a core meaning to create a new, unified concept. The first character, 适 (shì), carries the idea of being fitting, suitable, or appropriate for a situation. The second character, 用 (yòng), fundamentally means to use, employ, or apply. Therefore, their combination conceptually fuses these ideas to express the state or quality of "being suitable for application" or "fit for use", where something possesses the inherent suitability to be properly put into practice for a given purpose.