Drivetrain - a collection of components necessary to transmit torque from the engine to the wheels to get the car moving.

It encompasses the engine, transmission, clutch (on manuals) torque converter (automatics) and driveshafts.

If the torque is transmitted to the front, it's described as front-wheel drive.

To the rear - rear-wheel drive.

In front-wheel drive cars the gearbox and differential are one unit called a transaxle.

In rear-wheel drive cars the power has to be transmitted to the driving wheels from the engine at the front down the length of the car to the differential.

Four-wheel drives can have the differential located at both the front and rear.