Term: protocol

A protocol is a formal process of communication between two entities – usually computer programs running on the same or different computers. It’s often called the “language” used by those entities.

A protocol specifies what kind of information can be transferred, and the exact ‘terminology’ that must be used to make that transfer happen. Being computers, “exact” means just that – a very specific and formal language that both sides of the conversation must adhere to.

Mail protocols might specify authentication methods, ways to identify specific messages, recipients, senders, and what should happen to a message being transferred.

File-transfer protocols might specify nothing more than the name of the file and its contents, once again in a very formal and rigorous way.

Protocols of various kinds define almost all computer-to-computer and program-to-program interaction and information exchange.