自顶向下 zìdǐngxiàngxià top-down Origin Definitions Defs Strokes Stroke Words Sentences Sents 自 zì preposition from from; since; used in formal or written contexts to indicate a starting point in time or space顶 頂 dǐng nounlocative top the highest part of an object, such as a mountain peak or roof向下 xiàngxià adverbadjective downward moving or extending toward a lower position; down