idionym

noun3

1. •
   A mononym.
2. •
   (old-fashioned) A specific epithet; the name of a species.

   • Haworth's idionym “v-flava” has been changed to “v-flavum,” despite its acceptance, with explanation of derivation, by the Entomological Societies of Oxford and Cambridge […] — 1907
3. •
   A word that refers to one specific anatomical part.

   • In fact, this term, as coined and defined by me, is now an idionym, applicable to but a single part of the brain. — 1896