The word "昨夜" (zuóyè) is formed through the combination of two distinct characters, each contributing its own semantic meaning to create a specific temporal concept. The first character, "昨" (zuó), inherently means "yesterday" or "the day before," establishing a past timeframe. It is combined with the second character, "夜" (yè), which means "night." When joined, they follow a standard Chinese grammatical structure where a modifier ("昨") precedes the noun it describes ("夜"), resulting in the straightforward and literal compound meaning of "last night" or "the night that has passed."