director vs invigilator

director

noun
  • One who directs; the person in charge of managing a department or directorate (e.g., director of engineering), project, or production (as in a show or film, e.g., film director). 

  • A device that displays graphical information concerning the targets of a weapons system in real time. 

  • A counselor, confessor, or spiritual guide. 

  • The common axis of symmetry of the molecules of a liquid crystal. 

  • A member of a board of directors. 

  • That which directs or orientates something. 

invigilator

noun
  • A person who supervises students during an examination; a proctor 

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