Typical passenger cars have two axles. The axle is the shaft that connects a pair of tires and on which those tires rotate. A car has four tires, or two sets of tires, meaning that it has two axles.
Additional types of passenger vehicles may have more than two axles. A simple way to determine how many axles a vehicle has is to look at the vehicle from the side and count the pairs of tires. A car such as a stretch limousine that has three sets of tires has three axles. A car that has dual tires, two tires in the same tire well, does not have an additional axle.