frankpledge vs parricide

frankpledge

noun
  • A form of collective suretyship and punishment under English law among the members of a tithing. 

  • A decener: a member of a tithing bound in frankpledge. 

  • Any group so similarly answerable for the conduct of all its members and liable for collective punishment. 

  • The tithing itself. 

parricide

noun
  • The killing of a relative, especially a parent. 

  • Someone who kills a relative, especially a parent. 

  • The killing of a ruler, or other authority figure; treason. 

  • Someone who commits treason. 

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