These words are very commonly interchanged, it can be confusing however the end goal is to give the paint a more brilliant shine by bringing more depth and clarity to the paint. To keep it simple sometimes a “buff “ is reffered to as a single stage of paint correction which typically a more aggressive approach or “polishing” and a polish is usually used in the sense of a vehicle that requires a light “polishing” or “jeweling” of the paint to get rid of lighter swirls and other scratches introduced into the paint work. Typically a darker color paint will require more work to get the same result as a lighter colored car so expect darker cars especially black to take more time and more of an expense.