librarian vs supervisor

librarian

noun
  • A person who processes and organizes information. 

  • The keeper, manager of a library. 

  • One who cares for the publications, files etc. in a library, whether staff or volunteer. 

supervisor

noun
  • A person with the official task of overseeing the work of a person or group, or of other operations and activities. 

  • In certain states, an elected member of the governing body for a county which is called the board of supervisors. 

  • A person who monitors someone to make sure they comply with rules or other requirements set for them. 

  • A process responsible for managing other processes. 

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