There is no definitive answer to this question, as the classification of a vehicle can vary depending on who you ask. Some people might say that a Toyota Sienna is a van, while others might say it is an SUV. Ultimately, it is up to the individual to decide what they consider a van or SUV to be.
There are some key features that distinguish a van from an SUV. Generally, vans are boxier in shape and have more interior space, making them ideal for transporting goods or people. SUVs are typically more round and have less interior space, making them better suited for off-road driving.
However, there are many exceptions to these rules, and there are many SUVs that are larger and more spacious than some vans. Likewise, there are many vans that are better suited for off-road driving than some SUVs. So, ultimately, it is up to the individual to decide what they consider to be a van or an SUV.