As far as I can tell, it is what marketing whats it to be.
http://www.toyota-global.com/company/history_of_toyota/75years/vehicle_lineage/car/id80000002/
Lexus LX 450 is build body on frame but the name literally means Luxury crossover X.
If they want to sell it to the men, they call it an SUV. If they want to sell it to a Female, it is a CUV.
I will just leave this here. The 90's was soo much simpler.