master vs principal

master

adj
  • Main, principal or predominant. 

  • Original. 

  • Masterful. 

  • Highly skilled. 

noun
  • Someone who has control over something or someone. 

  • A parajudicial officer (such as a referee, an auditor, an examiner, or an assessor) specially appointed to help a court with its proceedings. 

  • A vessel having a specified number of masts. 

  • The original of a document or of a recording. 

  • A male dominant. 

  • A master's degree; a type of postgraduate degree, usually undertaken after a bachelor degree. 

  • The primary wide shot of a scene, into which the closeups will be edited later. 

  • A tradesman who is qualified to teach apprentices. 

  • The owner of an animal or slave. 

  • A skilled artist. 

  • Someone who employs others. 

  • A person holding an office of authority, especially the presiding officer. 

  • A person holding such a degree. 

  • The captain of a merchant ship; a master mariner. 

  • An expert at something. 

  • A device that is controlling other devices or is an authoritative source. 

  • A person holding a similar office in other civic societies. 

verb
  • To earn a Master's degree. 

  • To become the master of; to subject to one's will, control, or authority; to conquer; to overpower; to subdue. 

  • To be a master. 

  • To learn to a high degree of proficiency. 

  • To make a master copy of. 

principal

adj
  • Primary; most important; first level in importance. 

  • Chosen or assumed among a branch of possible values of a multi-valued function so that the function is single-valued. 

noun
  • The chief administrator of a school. 

  • A diapason, a type of organ stop on a pipe organ. 

  • The construction that gives shape and strength to a roof, generally a truss of timber or iron; or, loosely, the most important member of a piece of framing. 

  • A dancer at the highest rank within a professional dance company, particularly a ballet company. 

  • The primary participant in a crime. 

  • The first two long feathers of a hawk's wing. 

  • A security principal. 

  • A legal person that authorizes another (the agent) to act on their behalf; or on whose behalf an agent or gestor in a negotiorum gestio acts. 

  • The chief executive and chief academic officer of a university or college. 

  • The money originally invested or loaned, on which basis interest and returns are calculated. 

  • A partner or owner of a business. 

  • One of the turrets or pinnacles of waxwork and tapers with which the posts and centre of a funeral hearse were formerly crowned 

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