The word 取决于 is formed by combining the character 取, meaning "to take" or "to choose", with the character 于, a classical preposition meaning "from" or "by". This creates a conceptual whole where 取 implies an action or outcome that is actively selected or derived, while 于 introduces the source or basis for that action. Thus, the compound literally conveys the idea of "taking from" or "being chosen by", metaphorically evolving to express the state where one thing is decided or determined by another factor.