Meaning of PROTOCOL in English

pro ‧ to ‧ col AC /ˈprəʊtəkɒl $ ˈproʊtəkɒːl, -kɑːl/ BrE AmE noun

[ Date: 1400-1500 ; Language: Old French ; Origin: prothocole , from Late Greek protokollon 'first page of a document' , from kolla 'glue' ]

1 . [uncountable] a system of rules about the correct way to behave on an official occasion:

a breach of diplomatic protocol

2 . [countable] formal

a) an international agreement between two or more countries:

the Montreal Protocol on the protection of the ozone layer

b) a written record of a formal or international agreement, or an early form of an agreement

3 . [countable] technical an established method for connecting computers so that they can exchange information

4 . [countable] technical a set of rules that are followed when doing a scientific ↑ experiment or giving someone medical treatment

Longman Dictionary of Contemporary English.      Longman - Словарь современного английского языка.