exonym

noun1

1. •
   An external name for a place, people or a language used by outgroup members (such as foreigners) instead of ingroup members (such as native-language speakers).

   • “Mandarin” is what linguists call an exonym, an external name for a place, people, or language. And exonyms often tell of a history of how cultures met, fought, and interacted. — 2019