I think the phrase “sola scriptura” does have an historical meaning, though.
If you are going to let people define themselves, they aren’t always going to please everybody with their definitions.
For instance, on the Roman Catholic side, someone might call themselves “the only true church” caucus. Actually for all I know, someone does. I wouldn’t like it, but that is how they view themselves.
It may have historical meaning, but is it a doctrine as defined by a real dictionary — not wiki.