It states a legal fiction. It isn't a definition, unless "legal fiction" and "definition" are taken as synonyms.
Couple modern examples. A patent application is considered as received at the USPTO the day it is deposited as US Express mail. It is actually received at the USPTO a day or two later, but it is considered received when it actually hasn't been received. Legal fiction.
A person 26 years old is considered as a child under certain tax statutes. A person is considered a legal adult at age 18 most otherwise. The tax child is a legal fiction.
The 1790 naturalization act uses the "shall be considered as" language. This is not the same as "is."
Some legal fictions are theoretically out of constitution bounds. A 30 year old shall be considered as 35 years old for purposes of eligibility to POTUS, for example, contradicts the constitution. But otherwise, re-aging is a legit legal fiction if Congress feels like it.
It’s true that the 1790 act used the language of “shall be considered as” and was therefore invalid which the Congress recognized as an error and repealed it, but it does illustrate the thinking at the time.
Natural born citizen means born here of citizen parents.
You are so full of crap. You have no clue.
Is the phrase “the right to bear arms shall not be infringed” a legal fiction in your strange world?