Eco’s identification of certain attributes in regards to fascist Germany and Italy is just that - identification of certain attributes, and most definitely in no way a “definition.”

In order to have a workable definition of fascism, we would have to also acknowledge why it exists and for whose benefit - and this is where liberal treatises on fascism falls hopelessly short. You simply cannot properly investigate the causes of fascism without investigating the capitalist and colonialist structures that gives birth to it.