The term "motor vehicle" refers to any self-propelled vehicle that can move on a road or highway. There are various synonyms that can be used instead of this term. These include car, automobile, truck, bus, van, motorbike, motorcycle, and more. "Car" is the most common synonym for the term motor vehicle, while "automobile" is more formal. "Truck" refers to a heavy-duty motor vehicle used for transportation or hauling goods, while "bus" is a large motor vehicle designed to carry passengers. "Van" is a type of motor vehicle commonly used for transportation or delivering goods. "Motorbike" or "motorcycle" are synonyms for two-wheeled vehicles. In short, these synonyms can be used interchangeably, depending on the context.