Nazism is a fascist movement originally indigenous to Germany. A term coined from the German expression Nationalsozialismus (National Socialism). The most prominent Nazi political party was the National Socialist German Workers Party (NSDAP - Nationalsozialistische Deutsche Arbeiterpartei) led by Adolf Hitler.
A Neo-nazi movement became popular towards the end of the 20th century (especially among disaffected youths, known as skinheads). Neo-nazism exists in a number of countries, including Germany and the United States of America.
See also: History of Germany, doublespeak (for a discussion of the semantic implications of words such as "Nazi")