@JoeBobMack
I did look at another article or two and got the impression that the "white splotches on black" is the generally accepted but not universal version. Both "piebald" and "skewbald" are strictly about coloration, not a breed.
As per the second link I posted, piebaldism is actually a form of partial albinoism. It can affect any horse of any breed and any color.
You have to distinguish between piebaldism and piebald as a recognized color/pattern for certain breeds.
A horse with either can accurately be called piebald.
Looking at the article you were referring to, I think you need to pay attention to this:
When it comes to horses, a piebald horse is an exclusively black horse with white spots. British English uses this term the most often. In North American English, piebald horses are sometimes called "pinto."
In point of fact, as someone from the US, pinto is the only term I've heard for a black/white horse not suffering from piebaldism.