The word “Noble” means different things to the different realms and nations of Rassilon.
In Heligioland, where there is no king or court to hand out lands and titles, nobility is generally an informal title conferred upon any family who has acquired a great deal of land.
There is no formalized process for this occurrence. At some point, the people of the area simply start calling people Lord or Lady. This sometimes begins with not a little sarcasm, and it’s not necessarily a welcome change for those recently entitled, because it also confers responsibility, as the new Lord or Lady is expected to have a say in resolving local conflicts and to take the lead in financing the defense of surrounding lands.
Sometimes, nobility is a title conferred on an elected official, or an appointee, or a town elder. Sometimes, it passes to a son or daughter through sheer habit of use. Sometimes it does not. Sometimes, its informal use as a title continues even after the conditions that warranted the title have passed.