The word "上车" is formed through a direct and logical combination of its two component characters: "上", which depicts upward movement or the act of ascending onto a surface, and "车", which represents a wheeled vehicle, such as a car, bus, or cart. The formation visually and conceptually places the action of "getting on" in immediate relation to the object "vehicle", creating a compact, intuitive unit that means "to board" or "get on" the vehicle. It encapsulates the entire action of moving from a lower, external point to an interior or upper position on the conveyance in a single, spatially coherent idea.