This is the 3954th most frequent Chinese word.
交界
"Boundary" or "junction where two areas meet."
In this sentence, '交界' describes the physical intersection or meeting point of two countries' borders.
两国的边境在山谷处有交界。
The borders of the two countries intersect in the valley.
Here, '交界' refers to the transitional zone or interface between two different areas, nature and urban spaces.
自然与城市的交界处可以闻到泥土的芬芳。
At the meeting point of nature and the city, one can smell the fragrance of the soil.
In this context, '交界' metaphorically signifies the point of convergence between two abstract concepts, culture and technology.