My point was that they were not confused. They considered various terms axiomatic. "Arms" were known primarily as guns, and therefore required bullets, and so there was no need to explicitly define the characteristics of what was common knowledge of the time.
In the same manner, they knew what the meaning of "natural born citizen" was in 1787 because it was built on the same philosophical foundation as the nation itself was built upon. The very word "Citizen" is a clue as to what that philosophical foundation was. They explicitly chose not to use the word "Subject" to describe the people of the United States, though that was the normal term they inherited from the British common law. Where did they get the idea to use this word "Citizen" (which is from French and meant "City Dweller" up until the 14th century. *) to describe nationals?
When writing the Declaration of Independence, Jefferson initially wrote the word "Subject" and then rubbed it out and changed it to "Citizen."