captain vs first officer

captain

noun
  • A naval officer with a rank between commander and commodore. 

  • An honorific title given to a prominent person. See colonel. 

  • The head boy of a school. 

  • A maître d', a headwaiter. 

  • A chief or leader. 

  • An army officer with a rank between the most senior grade of lieutenant and major. 

  • The person lawfully in command of a ship or other vessel. 

  • One of the athletes on a sports team who is designated to make decisions, and is allowed to speak for his team with a referee or official. 

  • A commissioned officer in the United States Navy, Coast Guard, NOAA Corps, or PHS Corps of a grade superior to a commander and junior to a rear admiral (lower half). A captain is equal in grade or rank to a United States Army, Marine Corps, or Air Force colonel. 

  • The leader of a group of workers. 

verb
  • To act as captain 

  • To exercise command of a ship, aircraft or sports team. 

first officer

noun
  • The executive officer, second in command of a naval vessel. 

  • Air Transport Auxiliary rank corresponding to Flight Lieutenant in the Royal Air Force. 

  • Women's Royal Naval Service rank corresponding to Lieutenant-Commander in the Royal Navy. 

  • The copilot of an aircraft. 

  • The chief mate of a merchant ship. 

  • The most senior civil servant in the United States Foreign Service, with responsibility for running an embassy under the authority of and reporting to the ambassador. 

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