protocol

Concise Oxford English Dictionary © 2008 Oxford University Press:
protocol/ˈprəʊtəkɒl/

▶noun

• 1 the official procedure or system of rules governing affairs of state or diplomatic occasions.

  ■ the accepted code of procedure or behaviour in a particular situation.

• 2 the original draft of a diplomatic document, especially of the terms of a treaty agreed to in conference and signed by the parties.

  ■ an amendment to a treaty or convention.

• 3 a formal record of scientific experimental observations.

  ■ a procedure for carrying out a scientific experiment or a course of medical treatment.

• 4 Computing a set of rules governing the exchange or transmission of data between devices.

– origin ME (denoting the original note of an agreement): from OFr. prothocole, via med. L. from Gk prōtokollon ‘first page, flyleaf’.