The difference between a sedan, a coupe, and an SUV is the size and shape of the vehicle. Sedans are typically four-door cars with a large trunk, while coupes are typically two-door cars with a smaller trunk. SUVs are typically four-door cars with a higher ride height, more ground clearance, and more interior space than sedans or coupes. Additionally, sedans and coupes are usually designed for passenger use, while SUVs are designed for both passenger and cargo use.