The word 上路 is formed through the conceptual blending of its two component characters: 上 (shàng), which carries the core idea of "ascending", "boarding", or "embarking upon", and 路 (lù), which means "road", "path", or "journey". Their combination creates a single concept that metaphorically extends the literal action of "setting out on a road" to signify the broader, more abstract idea of beginning a venture, putting something into operation, or even, in a solemn context, departing on one's final journey. The formation relies on this intuitive, spatial metaphor where starting an action is visualized as stepping onto and moving forward along a path.