Meyer’s intention is to divide his text into three parts. First is the vocabulary, then the explanation and interpretation of the vocabulary, and finally the art of fencing itself. The purpose of this is three-fold.
The first is to avoid frustrating the reader. He is concerned that some readers will scorn his work because the terms are unfamiliar. This tells us that even in his day not everyone knew or agreed upon fencing terminology.
Secondly, if he included definitions while in the middle of explaining a technique then the reader would find it tiresome to read.
Finally, it is to demonstrate to the experienced practitioner that his art isn’t just “mummery” or stage fighting and actually has a rational foundation. This tells us that even in his day there was a distinction between real fighting and what actors do, the latter being “taken for the most worthless and useless folk in the world”.