From ACT Wiki
1. Information technology - security.
A set of rules for the reliable and secure transmission of data between devices.
For example, Hypertext Transfer Protocol, Secure (HTPS).
2. International law.
An international agreement, less formal than a treaty.
Sometimes used to amend the terms of a treaty.
Examples include the Natural Capital Protocol and the Kyoto Protocol.
Any accepted - or established - code of behaviour or procedure.