"SUV" doesn't mean anything specific. Look around you on the road: SUVs are the new minivans. People buying new cars today grew up in minivans, and the last thing you want to drive is the thing your mom drove. Give it another 20 years and I bet we see the minivan come back in style as kids growing up with SUVs now think of them as the soccer-mom-mobiles that they are.
It is a marketing term that means "we're going to sell you something you'll probably think of as a big car, but which only has to meet light truck standards". There was a time when something like a Jimmy or a Bronco was distinctly downmarket and likely to have utilitarian rubber floor mats rather than carpeting. (Yes, there were some "gentlemanly" vehicles in the general class, like the Range Rover and the Wagoneer, but most were all business.) CAFE regulations didn't include trucks, so we were sold trucks instead of cars. Now people want trucks that look like cars from the inside.
Actually, a lot of my whitewater paddling friends favor minivans over SUVs for a combination of being able to haul a lot of gear and ease of shuttling people.
The SUV term has been steadily stretched to cover vehicles that are less and less designed for anything other than a paved road and have less and less storage space.
SUV = obese car. This is an obese car, therefore its a SUV.
There are snarkier ways, like a car is a vehicle where 75% of the seats are empty almost all the time, whereas a SUV is a vehicle where 85% of the seats are empty almost all the time, so the cutoff is around 80% usually empty.
Slightly more seriously a SUV can be defined as a car that has a towing rating approved by the mfgr. I've never owned a car where the mfgr approves any towing weight at all, and I've never heard of a SUV that can't at least tow some minimal weight.
Counterpoint: my Volvo has a 1540lb towing rating approved by Volvo. It is not an SUV.
The lines are ambiguous. "SUVs" nowadays range from minivans that don't look like minivans (crossovers) like the Ford Edge to actual SUVs like the Jeep Grand Cherokee. My personal definition is if you can take it off road on a trail with no mods and there is no bed, it's definitely an SUV. If you can't realistically take it on a trail, it's a crossover.
