The word "升级" is formed by combining two meaningful characters into a new, composite idea. The first character, "升" (shēng), carries the core meaning of "to rise", "ascend", or "hoist". It is paired with "级" (jí), which means "level", "grade", or "step". When placed together, they create a direct, cause-and-effect visual metaphor: one "rises" through or to a new "level", perfectly capturing the concept of an upgrade, promotion, or advancement as a single, seamless action.