It's mostly semantics, but a CUV is commonly known as a large wagon type vehicle with a unibody chassis and a transverse engine. They are usually car based rather than truck based. Basically it is the new way of saying station wagon, however they tend to be slightly more capable with AWD and have a higher stance than your average avant/shooting brake/wagon/estate.
If the VUE had come out a few years later, they might actually call it a CUV, but I'm not sure if it has a unibody or body on frame chassis, I'm sure someone could comment on that. The CUV moniker is actually used more on the larger vehicles - those that would be seen as an irresponsible resource hog as a traditional SUV.
Here's a fairly well written description, from wikipedia:
"A crossover SUV (also called CUV for Crossover Utility Vehicle) or XUV is an automobile with a sport utility vehicle appearance but is built upon a more economical and fuel-efficient unibody construction.
The CUV nomenclature was created by automotive marketing departments to move away from the station wagon, which has declined in popularity, and the SUV, which has been stigmatized by some people in American culture as environmentally-unfriendly, over-sized, and wasteful with fuel. The word "CUV" or "Crossover" is not a ubiquitous term and is primarily used by people in the automotive industry.
The nomenclature's unpopularity may be due to the fact that some CUVs are compact- to mid-sized SUVs built with car drivetrains and suspensions (Lexus RX330, BMW X3), while most CUVs are actually station wagons or 5-door hatchbacks with truck-like characteristics such as elevated suspensions and upright seating (Volvo XC90, Ford Taurus X, Cadillac SRX).
In some cases, marketing departments may sometimes blur the line between vehicle body types."
Head over to BMW and they list their X5 as a SAV (sport activity vehicle).
Their "new" vehicle the X6 is a SAC (sport activity coupe) even though it has four doors and resembles the earlier Subaru Outback cars.
They aren't fooling anyone.