autocrat vs dictator

autocrat and dictator both are nouns.

Word	Noun	Adjective	Verb	Adverb
autocrat	Yes	No	No	No
dictator	Yes	No	No	No

As nouns, dictator is a hypernym of autocrat; that is, dictator is a word with a broader meaning than autocrat:

Other hypernyms of autocrat include potentate.

autocrat (noun)	dictator (noun)
a cruel and oppressive dictator	a ruler who is unconstrained by law
	a person who behaves in a tyrannical manner
	a speaker who dictates to a secretary or a recording machine