aide-de-camp vs warrant officer

aide-de-camp

noun
  • A military officer who serves as an adjutant to a higher-ranking officer, prince or other high political dignitary. 

warrant officer

noun
  • An officer holding rank by virtue of a warrant rather than a commission. 

  • An officer assigned to execute warrants and other writs. 

How often have the words aide-de-camp and warrant officer occurred in a corpus of books? (source: Google Ngram Viewer )