English Reference
noun

protocol

n.
US /ˈpɹoʊtəˌkɑɫ/ UK /pɹˈəʊtəkˌɒl/ pro·to·col UK spelling protocol's, protocol's, protocoled, protocoling, protocolled, protocolling

  1. 01 B2 Upper Intermediate Formal

    the official rules for how people should behave at formal events or in government.

    the system of rules and conventions governing correct etiquette and precedence between diplomatic representatives and heads of state.

    Simple

    According to royal protocol, you must wait for the Queen to speak first.

    In context

    The visiting dignitaries were careful to observe every nuance of diplomatic protocol to avoid any perceived slight during the summit.

  2. 02 C1 Advanced TechnicalAcademic Medicine

    a detailed plan or set of steps for a scientific experiment or medical treatment.

    a formalised set of procedures to be followed in a clinical trial, medical treatment, or scientific experiment.

    Simple

    The hospital has a strict protocol for cleaning surgical tools.

    In context

    The research team strictly adhered to the experimental protocol to ensure that the results could be accurately replicated by other laboratories.

  3. 03 C1 Advanced Technical Computing

    a set of rules that computers use to talk to each other and send information.

    a standardised set of rules governing the format and transmission of data between devices in a network.

    Simple

    HTTP is the protocol used for transferring data on the web.

    In context

    The software update failed because the legacy hardware was incompatible with the new security protocol implemented by the server.

  4. 04 C1 Advanced Formal Law

    a formal document that records an agreement between countries.

    an official record of a diplomatic negotiation or an amendment to an international treaty.

    Simple

    The two nations signed a new protocol to protect the environment.

    In context

    The Kyoto Protocol established legally binding obligations for developed countries to reduce their greenhouse gas emissions.

Her Prevent case was closed while she was investigated by MI5, as is protocol at such a time.

The Guardian· 13 Aug 2026

Until those protocols are developed, the default will often be to treat a standing wall as debris rather than a valuable building block for the future.

The Conversation· 13 Aug 2026

Borrowed from Middle French protocolle, protocole (“document, record”), from Late Latin protocollum (“the first sheet of a volume (on which contents and errata were written)”), from Byzantine Greek πρωτόκολλον (prōtókollon, “first sheet glued onto a manuscript”), from πρῶτος (prôtos, “first”) + κόλλα (kólla, “glue”). Doublet of collage, collagen, and colloid.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Origin gkm πρωτόκολλον
Level C1 · Advanced
Frequency Common
Updated