2WD – 2-wheel drive
When a motorized vehicle has a transmission that delivers power only to the front or to the rear wheels. 2-wheel drive permits two wheels to receive power from the engine at the same time. For a four wheeled vehicle, this term refers to vehicles that are capable of powering two wheels simultaneously at most. For a two wheeled vehicle like a motorcycle or a bicycle, this term refers to vehicles that can deliver power to both the front and the back wheel.
4WAS – Four wheel anti skid
A system for traction control on vehicles with four wheel drive. This term refers to an anti-slip control system that is designed to anticipate traction loss and thwart it. When evoked, four wheel anti skid enhances driver control by sending torque to the wheels.
4WD – 4-wheel drive
When a motorized vehicle has a transmission that delivers power to all four wheels simultaneously. This term refers to a drive train that is capable of sending torque to all four of the wheels on a vehicle, but that does not inevitably mean all wheels have to be powered at the same time. A four wheel drive vehicle may be accoutered with “Part-time 4WD,” “Automatic 4WD,” or “Full-time 4WD.” 4-wheel drive is often used synonymously with “all-wheel drive.”
4WS – Four-wheel steering
This term refers to a vehicle’s ability to steer both the front wheels and the rear wheels. Four-wheel steering is a system that allows the driver to have better handling of the vehicle by permitting the rear wheels to be maneuvered instead of merely following the direction of the front wheels. This allows for sharper turns to be made as the rear wheels turn in the opposite direction from the front wheels.
4X4 – 4-wheel drive, see 4WD
This refers to a vehicle with four-wheel drive or “four by four.” 4X4 stands for a vehicle with four wheels that is capable of sending power to all four of the wheels, but it does not necessarily mean power has to be delivered to all of the wheels at the same time. This term means a motorized vehicle has a drive train that is able to deliver torque to the four wheels.