Input (grade 13): For vehicles with more than four wheels, AWD means all wheels drive the vehicle, to varying degrees of engagement, while 4WD means only four of the wheels drive the vehicle continuously.
Output (grade 12): A Four-wheel drive (also called 4WD, 4x4 ("four by four"), all-wheel drive, or AWD) is a vehicle on which all four wheels get power from the engine to move forward.