commander vs commanding officer

commander

noun
  • A naval officer whose rank is above that of a lieutenant commander and below that of captain. 

  • One who exercises control and direction of a military or naval organization. 

  • A designation or rank in certain non-military organizations such as NASA and various police forces. 

  • One who exercises control and direction over a group of persons. 

  • A rank within an honorary order: e.g. Commander of the Legion of Honour. 

  • Any of various nymphalid butterflies of the Asian genus Moduza. 

  • A heavy beetle or wooden mallet, used in paving, in sail lofts, etc. 

commanding officer

noun
  • The officer in command of, and typically having ultimate authority over, a military unit. 

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