The word 下雨 is formed through a direct visual and conceptual combination of its two component characters: 雨 (yǔ), which pictographically represents rain with its lines depicting falling droplets, and 下 (xià), meaning "down" or "below". When placed together, they create a dynamic ideographic sequence, first establishing the subject (rain) and then immediately describing its primary action and direction (falling down), resulting in a concise scenic composition that means "to rain" by literally depicting "rain falling downward".