Endonym (also autonym "self name") is a Greek/English word for a name that a people or country calls themselves or their language. Exonym (also xenonym "foreign name") is a Greek/English word for the opposite, or what a stranger would call someone else's country, people or language. Endonym means "inside name"; while exonym means "outside name".
Source: tatoeba (11746169)
Near-synonym: type variety
Source: wiktionary
Deutsche is the autonym of the people known in English as Germans.
Source: wiktionary
As a general principle, the heading of the main entry of the book should be in the form in which the book itself is published; that is, if it is published under an autonym let the autonym be given, if under a pseudonym, then let the pseudonym be given, and if the book be anonymous, then let the fact be stated.
Source: wiktionary