Protocols - Shortcuts to Authorship

Protocol (diplomacy), the etiquette of diplomacy and affairs of state
Protocol (politics), a logbook or other artifact of a political meeting between persons from different nations
Protocol (treaty), a treaty or international agreement that supplements a previous one
Communications protocol, a set of rules governing communication between electronic devices
Protocol (computing), a set of rules governing communication within and between computing endpoints
Protocol (object-oriented programming), what or how unrelated objects use to communicate with each other in object-oriented computer programs

A protocol a contract that binds communicating parties. That is, a protocol states what messages and what responses will be communicated. In a sense, the event function defines the protocol. Protocols mean that we do not have to do everything, we can rely on some contracts being fulfilled.