I just realized why it's called "The Fellowship of the Ring". The fellowship is a Genossenschaft, a very important concept in the history of German corporate law, translated as "Fellowship". It could be a Germanic household, clan or village, or, notably, a warrior band. As Berman puts its, citing Gierke (who was celebrated by Maitland) (Law and Revolution at 217) "the Genossenschaft derived its unity and its purpose not from a higher authority, whether divine or human, but solely from within itself, that is, solely from the voluntary coming together of the members to achieve an end set by themselves." In the LOTR story, the power that binds the Genossenschaft together is pitted against the evil power of the One Ring ("and in the darkness bind them") that seeks to unite itself back to the Dark Lord. The Fellowship is broken, but not really, as all its members carry out its purpose in different ways, while Frodo and Sam carry on its purpose directly and play out a tale of heroic warrior-friendship.