A "lemon" is a car that is dysfunctional, even though you had no idea when you bought it. Clearly, cars do wear down over time, just like any other product. Repairs are expected. However, if the car is not up to the realistic standards for a vehicle, then you need to get your money back from the company that produced it. You have rights as a buyer.
How do you know if the car is not up to those standards? There are some repair requirements that have to be met. Specifically, under West Virginia law, the car needs to have a "substantial nonconformity" that you find after you make your purchase. You then have to use the warranty to try to have it repaired. If this is unsuccessful, despite a "reasonable" number of attempts and the car is still defective, then it may be a lemon.