Master vs headship

Master

noun
  • A person holding a master's degree, as a title. 

  • The title of the eldest son of a Scots lord. 

  • The title of the head of certain colleges and schools. 

  • The owner of a slave, in some literature. 

  • Used as the title of a dominant. 

  • A master's degree. 

  • A religious teacher, often as an honorific title. 

  • Prepended to a boy's name or surname as a (now somewhat formal) form of address. 

name
  • MasterCard 

  • One of the triune gods of the Horned God in Wicca alongside the Father and Sage and representing a boy or a young man 

headship

noun
  • The position of a headmaster or headmistress. 

  • The position of a head or chief. 

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