chief mate vs warden

chief mate

noun
  • In the merchant navy, the officer who is second in command to the captain, and whose primary duties include managing the maintenance and upkeep of the vessel. 

warden

noun
  • An official charged with supervisory duties or with the enforcement of specific laws or regulations; such as a game warden or air-raid warden 

  • A variety of pear. 

  • A governing official in various institutions 

  • A chief administrative officer of a prison. 

verb
  • To carry out the duties of a warden. 

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