authoritarianism vs autocracy

authoritarianism

noun
  • A form of government in which the governing body has absolute, or almost absolute, control. Typically this control is maintained by force, and little heed is paid to public opinion or the judicial system. 

autocracy

noun
  • A form of government in which unlimited power is held by a single individual. 

  • An instance of this government. 

How often have the words authoritarianism and autocracy occurred in a corpus of books? (source: Google Ngram Viewer )