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. 
Ethnonyms can change in character over time; while originally socially acceptable, they may come to be considered offensive. For instance, the term Gypsy has been used to refer to the Romani. Other examples include Vandal, Bushman, Barbarian, and Philistine.
The ethnonyms applied to African Americans have demonstrated a greater evolution; older terms such as colored carried negative connotations and have been replaced by modern-day equivalents such as African-American.[ citation needed] Other ethnonyms such as Negro have a different status. The term was considered acceptable in its use by activists such as Martin Luther King in the 1960s,  but other activists took a different perspective. In discussing an address in 1960 by Elijah Muhammad, it was stated "to the Muslims, terms like Negro and colored are labels created by white people to negate the past greatness of the black race". 
Four decades later, a similar difference of opinion remains. In 2006, one commentator suggested that the term Negro is outdated or offensive in many quarters; similarly, the word "colored" still appears in the name of the NAACP, or National Association for the Advancement of Colored People.
In English, ethnonyms are generally formulated through suffixation; most ethnonyms for toponyms ending in -a are formed by adding -n: America, American; Austria, Austrian. In English, in many cases, the word for the dominant language of a group is identical to their English-language ethnonym; the French speak French, the Germans speak German. This is sometimes erroneously overgeneralized; it may be assumed that people from India speak "Indian",  despite there being no language which is called by that name.
Generally, any group of people may have numerous ethnonyms associated with the political affiliation with a state or a province, with geographical landmark, with the language, or another distinct feature. Ethnonym may be a compound word releted to origin or usage, polito-ethnonym indicates that name originated from the political affiliation, like Belgian for inhabitants of Belgium that have their own endonyms; topo-ethnonym refers to the ethnonym derived from the name of the locality, like Uralians for the inhabitants of the geographical area near the Ural mountains that have their own distinct endonyms. Classical geographers frequently used topo-ethnonyms ( demonyms) as substitute for ethnonyms in general descriptions or for unknown endonyms. Compound teminology is widely used in professional literature to discriminate semantics of the terms.
- Aboriginal Rountable (1995): LCSH for ATSI People.
- Jr., Martin Luther King,; Holloran, Peter; Luker, Ralph E.; Penny A. Russell (1 January 2005). The Papers of Martin Luther King, Jr.: Threshold of a New Decade, January 1959-December 1960. University of California Press. p. 40. ISBN 978-0-520-24239-5. Retrieved 29 July 2013.
- Message from the Wilderness of North America. A Journal for MultiMedia History article.
- "The game of the name" (PDF). Baltimore Sun. 1994-04-03. Archived from the original (PDF) on 2011-05-15. Retrieved 2011-01-19.
- Bourne, Jill; Pollard, Andrew (26 September 2002). Teaching and Learning in the Primary School. Taylor & Francis. p. 34. ISBN 978-0-203-42511-4. Retrieved 29 July 2013.