alumnus vs preceptor

alumnus

noun
  • A male pupil or student. 

  • A student of any gender. 

  • A male graduate. 

  • A graduate of any gender. 

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 alumnus and preceptor occurred in a corpus of books? (source: Google Ngram Viewer )