edict vs ukase

edict

noun
  • A proclamation of law or other authoritative command. 

ukase

noun
  • Any absolutist order or arrogant proclamation 

  • An authoritative proclamation; an edict, especially decreed by a Russian czar or (later) emperor. 

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