protocol
US /ˈproʊ.t̬ə.kɑːl/
UK /ˈproʊ.t̬ə.kɑːl/

1.
the official procedure or system of rules governing affairs of state or diplomatic occasions
:
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The diplomats followed strict protocol during the negotiations.
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There is a specific protocol for addressing royalty.
2.
a system of rules that explains the correct way to do something
:
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The new software uses a secure communication protocol.
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The medical team followed a strict protocol for patient care.