What is the historical context of these two terms?
Why are they distinct? And why are they needed?
What pragmatic utility is there in knowing how these two terms differ?
In terms of Emacs/Emacs Lisp, where are they used/how are they used/why are they used?
(A solid example would be nice).
I am confused because I see no correlation anywhere in any modern-day files/GUI as to why I should know the differences between the meanings of font foundry and font family. But they seem so vital to know when dealing with fonts.