Those who read Tolkien deeply and wish to discover more about his Legendarium could have noticed the word Gnomes in the early versions of the tales that the Professor used to refer to the Elves known as the Noldor. Later, though, he abandoned the term opting only for the Quenya word Noldor instead. This change has a history.
The world of Arda is full of fascinating characters and creatures not found in other tales or mythologies or, in any case, not in the same form J. R. R. Tolkien envisioned them in his books. Owing to a well-developed system of languages, it was possible for the Professor to use precise words in his invented tongues, for example in Quenya or Sindarin, to name those characters whose identities it was not always possible to render accurately in English. In a letter Tolkien mused that he was “under the difficulty of finding English names for mythological creatures with other names”. He did it so as not to shower his readers with “a string of Elvish names”, but some interpretations were false, according to Tolkien himself. One of the most interesting examples of this is Istari or the Wizards.