An ethnonym (from the Greek: ἔθνος, éthnos, "nation" and ὄνομα, ónoma, "name") is a name applied to a given ethnic group. Ethnonyms can be divided into two categories: exonyms (whose name of the ethnic group has been created by another group of people) and autonyms, or endonyms (whose name is created and used by the ethnic group itself).
As an example, the ethnonym for the ethnically-dominant group in Germany is the Germans. That ethnonym is an exonym used in English but itself comes from Latin. Conversely, Germans themselves use the autonym of Deutschen. Germans are indicated by exonyms in many other European languages, such as French (Allemands), Italian (tedeschi), Swedish (tyskar) and Polish (Niemcy).
Numerous ethnonyms can apply to the same ethnic or racial group, with various levels of recognition, acceptance and use. The State Library of South Australia contemplated this issue when considering Library of Congress Headings for literature pertaining to Aboriginal and Torres Strait Islander people. Some 20 different ethnonyms were considered as potential Library of Congress headings, but it was recommended that only a fraction of them be employed for the purposes of cataloguing.