The constant velocity joint (CV joint) is a part of the front-wheel drive system that allows the wheels to turn at different angles while still transmitting power from the engine to the wheels. When a CV joint is worn out, it can make a knocking noise when the vehicle is turning. The side of the car that the noise is coming from depends on which CV joint is worn out.
If the noise is coming from the left side of the car, then it is likely that the left CV joint is worn out. If the noise is coming from the right side of the car, then it is likely that the right CV joint is worn out.
In either case, it is important to have the CV joint repaired or replaced as soon as possible to avoid further damage to the vehicle.