The word G. rôn⁽²⁾ “liver” appeared in the Gnomish Lexicon of the 1910s, but its etymology is unclear (GL/65). Q. rāna “moon” was written in pencil nearby, but this seems to be from an earlier layer of the lexicon, and may be unrelated.

Neo-Sindarin: I’d retain ᴺS. rôn “liver” for purposes of Neo-Sindarin, perhaps as a derivative of the later root √RON “solid, firm”, since (a) there are no later words for “liver” and (b) the word rôn does not appear with any other meaning in later writings.