concordat vs protocol

concordat

noun
  • A formal agreement between two parties, especially between a church and a state; specifically, an agreement between the Pope and a government. 

protocol

noun
  • An amendment to an official treaty. 

  • A set of formal rules describing how to transmit or exchange data, especially across a network. 

  • The set of instructions allowing a licensed medical professional to start, modify, or stop a medical or patient care order. 

  • The official rules and guidelines for heads of state and other dignitaries, governing accepted behaviour in relations with other diplomatic representatives or over affairs of state. 

  • The official formulas which appeared at the beginning or end of certain official documents such as charters, papal bulls etc. 

  • The minutes, or official record, of a negotiation or transaction; especially a document drawn up officially which forms the legal basis for subsequent agreements based on it. 

  • The first leaf of a roll of papyrus, or the official mark typically found on such a page. 

  • The original notes of observations made during an experiment; also, the precise method for carrying out or reproducing a given experiment. 

  • An accepted code of conduct; acceptable behaviour in a given situation or group. 

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