A hub on a car is defined as the central part of the wheel where the shaft passes through. The hub rotates which in turn revolves the shaft or axle and propels the vehicle in the direction the driver wishes to go.
1 Additional Answer
A car hub is an automobile device that houses the wheels bearings. It also holds the wheels studs and has the drum brake attached to it. The car hub can also be found on the fans and propellers where it is centrally located.