headteacher vs preceptor

headteacher

noun
  • The most senior teacher in a school who is responsible for its management and administration. 

preceptor

noun
  • A teacher or tutor. 

  • A doctor who gives practical training to medical students, nurses etc. 

  • The head of a preceptory of Knights Templar. 

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