The Titius-Bode rule's fit to the solar system was a bit clunky at best, and it was not really testable in its day. It could not have been used to predict something else, and then that prediction tested. In that sense the whole thing was not in keeping with modern standards of what might be expected to refer to something as a law.
And yet now it is very often called "Bode's Law" by many people. I remember reading about it in several (now considered 'old') introductory astronomy books, possibly even grade school text books. Even if it wasn't given any scientific weight, I always remember it being called a "law", rather than a rule.
On the other hand, the Rydberg formula had some predictive ability, and yet it's not commonly referred to as a law or a rule, just a formula.
How and when did the Titius-Bode rule first become commonly known as a "law"? Is there a first instance of it being promoted to "law" status?
note: As an aside, HSMSE has one instance of reference, and Titius-Bode rule is used.