mononym

noun2

1. •
   A single name or term by which a person, thing, etc., is known.

   • The atlas and axis have special names, but most of the vertebra, like the ribs, are merely numbered ; among the arteries, the aorta only has a mononym — 1891
2. •
   A single term for a thing or concept, allowing for no synonyms.

   • After usage has created consensus on a mononym, it becomes possible to treat the accepted (preferred) forms in a terminographic glossary... — 1997