My motorcycle is GN125H. What does GN mean? And what does AX100 AX mean?

My dear friends on the first and second floors, please don’t pretend to be knowledgeable and pretend to be experts. GN, AX, etc. represent different engine models. How can 100 represent horsepower? How can an ordinary motorcycle have 100 horsepower? Isn’t that a big joke? 100 just means that the displacement of the engine is 100CC, and "below 100 is a two-stroke, and above 100 is a four-stroke" is even more ridiculous. Two-stroke and four-stroke just mean that the working principle of the engine is different. It is related to the displacement. It doesn’t matter at all, a 50CC moped can also have a four-stroke engine!