During the 20th century, Italy and Germany mastered two terrible and related ideologies - fascism and Nazism. The end of World War II did not mean the end of the bloody regimes in Europe. The post-war ideological squabbles resulted in the fact that the words fascism and Nazism were used interchangeably over time. Today I would like to straighten this point.
Nazism and Fascism
Nazism and fascism are not identical concepts and we should not use them interchangeably. If we want to be precise in speaking about the history of the 20th century, we need to recognize their differences. First of all, the main difference lies in the origins of these two ideologies. Fascism ruled in Italy and Nazism was in Germany. Origin is not the only discrepancy. German Nazism evolved into Italian fascism, but with the difference that it brought racial and anti-Semitic issues to the fore. At least until the end of the 1930s, these issues were not of primary importance in Italy under the rule of Benito Mussolini. It is worth mentioning that about 200 Jews took part in the "March to Rome" alone (according to the data provided by Polish Wikipedia). Jews also held important positions in fascist Italy, for example Aldo Finzi, a member of the Great Fascist Council and deputy interior minister. Later, under the influence of the policy of the Third Reich, anti-Semitic moods began to grow in Italy as well. 
Benito Mussolini and Adolf Hitler - Fascism or Nazism?
In Poland, post-war propaganda led to the fact that over time, however, fascism was assigned to Germany. The rhetoric of the Polish People's Republic was largely based on frightening society with the return of the Third Reich and the revision of the new western borders. Meanwhile, the use of the word Nazism, derived from the German word "Nationalsozialismus" meaning National Socialism, was not convenient. It was precisely because of the socialist word-forming origin of Nazism that it was inappropriate to use it in the new socialist Poland. Hence, references to related fascism were common. Incidentally, a similar rhetoric was used in the Soviet Union itself.