As quoted from Wikipedia.org, it appears pretty accurate.
A gross vehicle weight rating (GVWR) is the maximum allowable total weight of a road vehicle or trailer that is loaded, including the weight of the vehicle itself plus fuel, passengers, cargo, and trailer tongue weight. In the United States, two important GVWR limitations are 6,000 pounds (2,721 kg) and 8,500 pounds (3,856 kg). Vehicles over 6,000 pounds are restricted from many city roadways (though there is some dispute about whether this restriction is for actual curb weight or GVWR), and vehicles over 8,500 pounds do not have to display EPA estimated fuel mileage or a Monroney sticker nor are they subject to state emissions testing.
Most U.S. cars have a placard (sticker) with this information. It is located typically either in the driver's side door or doorframe, owners manual, or also may be present on another sticker immediately under the hood near the radiator, although that sticker more typically contains information about the size of the motor, various fluid capacities, etc.
Most U.S. commercial trucks (especially semi-trailer trucks and dump trucks) are required by licensing authorities to have this information printed on the outside of the vehicle and for it to be clearly visible from a specified distance. Many do so by painting these numbers in a large font on the driver's side of the truck near the door.
Gross weight is often confused with curb weight, which represents the weight of the vehicle with no passengers or cargo. The difference between gross weight and curb weight is the total passenger and cargo weight capacity of the vehicle. For example, a pickup truck with a curb weight of 2000 pounds might have a cargo capacity of 3000 pounds, meaning it can have a gross weight of 5000 pounds when fully loaded.
For vehicles containing no fuel or driver, the gross weight is the sum of the tare weight (the unladen vehicle weight) and the weight of the load carried. For the measuring of loads picked up at a depot or materials yard (such as gravel or rock, or other bulk goods), the weight of the driver, fuel, and existing loads are assumed to be constant between the weighing of the vehicle upon entrance (tare) and laden (gross) upon exit. Such weights are determined by a specialized scale called a weigh bridge, and such scales will usually have a computing function within the display to compute tare weight.