1 [U] a system of fixed rules and formal behaviour used at official meetings, usually between governments:
a breach of protocol * the protocol of diplomatic visits
2 [C] (technical) the first or original version of an agreement, especially a TREATY between countries, etc.; an extra part added to an agreement or TREATY:
the first Geneva Protocol * It is set out in a legally binding protocol which forms part of the treaty.
3 (computing) a set of rules that control the way data is sent between computers
4 (technical) a plan for carrying out a scientific experiment or medical treatment
