What does the 'quattro' system in Audi mean?

I've heard that Audi has a 'quattro' system, but I'm not sure what it does or how it works. Can someone explain it to me?

The quattro system in Audi is their all-wheel drive system. It distributes power to all four wheels, providing better traction and handling in all weather conditions.

Having driven both Audi models with and without quattro, I can confidently say that the quattro system significantly improves the handling and control of the car.

Audi's quattro system is designed to detect wheel slip and send power to the wheels with the most traction. This results in better acceleration and stability on both wet and dry roads.