When I was protestant, I asked about that. I was told that “dueterocanonical” means “second canon”. That is, that the Catholic Church added them to the Canon much later. Of course, I was also told that “who ever adds to this will be cursed”, from Revelation, was addressing this (i.e. adding books to the Bible).
You are correct “Deuterocanonical” does mean 2nd canon however the “term” came into use in the 16th Century a long time after the “Canon” or “Bible” had been closed.
The reason behind this is that the Jews around 100 started ommiting these books claiming they were NOT biblical.
Let’s see how these claims stack up.
The Septuagint, the OT that Jesus and all His Apostles (well most of them anyway) quote did have these books in it.
We know this because we have quotes from these books in the NT.
Further, more recently the Dead Sea Scrolls have been found with fragments from precisely these books.
Even further these books are a damning indictement of the Jews that want to attack Jesus’s claims. Any wonder why they wanted to silence them?
For all these reasons we keep them in the “Bible”
By the way and as a sidenote when Luther et all started their revision of the “Canon” they compared the OT from KJ with the OT that the Jews of the day were using, and they “discovered” that they did NOT include those books.
They TRUSTED and believed the word of 16th Century NON Christians over the teachings of the true Church.
The irony of this is amazing
