As the comment says, looking at the web site you posted there seems to be a couple of flavors of engine for your car. So unless we know the displacement (it would say 2.3L V6 for example) we can't say exactly for your car. There are 5 or 6 flavors listed for your car, from a 1.8L 4 cyl, to a 4.0L V8 ( would love to see how this is stuffed into a Passat lol). All of which will have different belt setups. Here's a general overview of the types.
- Timing belt = timing chain = (generally) toothed belt
- These are all connecting mechanisms to keep the pistons and the valves in time with each other. They all connect the crank pulley with the cam shaft pulley (or pulleys) so that the valves are always in time with the position of the pistons.
- Toothed belt refers to any belt that has teeth on the under side, but the manuals for your car seem to refer to the timing belt as "the toothed belt". A timing belt is always toothed because a "V" belt can slip, and that would be catastrophic for your engine (if it's an interference engine, one where the valves will collide with the pistons if they open at the wrong time).
- The timing belt and timing chain do the same job, but one is literally a chain. I did not mean to imply that it's a belt.
- Serpentine belt = accessories belt
- A belt that is generally on the font of the engine that runs your alternator, sometimes the water pump, power steering pump, etc.
I feel like I'm forgetting one (or two) but they are not coming to me right now.
For the most part, every car has it's own arrangement for these belts. Even the same type of car, the various engine types that are available can all have different belt setups. But this is at least a start on what the different belts are called and what they do.
I hope that helps!