I just want to add my two cents.
Nazism could easily could be considered fascism, and the King of England's rule could be considered tyranny.
Here are the Websters definitions of both terms.
fascism - 1 often capitalized : a political philosophy, movement, or regime (as that of the Fascisti) that exalts nation and often race above the individual and that stands for a centralized autocratic government headed by a dictatorial leader, severe economic and social regimentation, and forcible suppression of opposition2: a tendency toward or actual exercise of strong autocratic or dictatorial control
tyranny - 1: oppressive power ; especially : oppressive power exerted by government 2 a: a government in which absolute power is vested in a single ruler ; especially : one characteristic of an ancient Greek city-state b: the office, authority, and administration of a tyrant3: a rigorous condition imposed by some outside agency or force 4: a tyrannical act