The word 晚上 is formed by combining two characters that together create a conceptual picture of time. The first character, 晚, means "late" or "evening", establishing the temporal frame. The second character, 上, which literally means "up" or "upon", is used here in a metaphorical sense to indicate the "onset" or "arrival" of that period. Thus, the term literally conveys the idea of "upon the coming of lateness", picturing the time as the late part of the day settles in.