protocol

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.

• (Received Pronunciation) IPA^(key): /ˈpɹəʊtəˌkɒl/

• Audio (Southern England):

  (file)

• (General American) IPA^(key): /ˈpɹoʊtəˌkɑl/, /ˈpɹoʊtəˌkɔl/, /ˈpɹoʊtəˌkoʊl/

• Audio (US):

  (file)

• Hyphenation: pro‧to‧col

protocol (countable and uncountable, plural protocols)

1. (now chiefly historical) The minutes, or official record, of a negotiation or transaction; especially a document drawn up officially which forms the legal basis for subsequent agreements based on it.
   • 1842, Thomas Campbell, Frederick the Great and his Times, volume II, page 47:

     Another account says that, on the morning of the 31st of May, the king delivered to the prince-royal the crown, the sceptre, and the key of his treasure and gave him his blessing. The privy-counsillor Vockerodt drew up at his desire a protocol of the transaction.

2. (international law, now rare) An official record of a diplomatic meeting or negotiation; later specifically, a draft document setting out agreements to be signed into force by a subsequent formal treaty.
   • 1970, Matthew Smith Anderson, The Great Powers and the Near East, 1774-1923, page 32:

     The terms of this protocol formed the basis for the Treaty of London signed by the British, French and Russian governments on 6 July 1827.

3. (international law) An amendment to an official treaty.
   • 2002, Philippe Sands, Principles of International Environmental Law, p. 917 n. 253:

     The 1992 Protocol amended the definitions of other terms, including ‘ship’, ‘oil’ and ‘incident’: Art. 2.

4. The first leaf of a roll of papyrus, or the official mark typically found on such a page.
   • 1991, Leila Avrin, Scribes, Script, and Books, page 146:

     They marked the beginning of each scroll with their protocol, a practice that continued in the papyrus trade in the Byzantine Empire [...] into the Islamic period, when there were bilingual protocols in Greek and Arabic.

5. The official formulas which appeared at the beginning or end of certain official documents such as charters, papal bulls etc.
   • 1985, Archivum Historiae Pontificiae, volume 23, page 14:

     The protocol of the bull contains elements that appear to be formulaic by the time of John XVIII 's pontificate.

6. (sciences) The original notes of observations made during an experiment.
   • 1931, Gye & Purdy, The Cause of Cancer, page 194:

     The following is an abstract of the protocol of the experiment: Tumour extract.—A measured 16 c.c. of minced Rous Sarcoma tissue was ground with sand and extracted with 400 c.c. of 0.8-per-cent. saline.

7. (sciences) The precise method for carrying out or reproducing a given experiment.
8. The official rules and guidelines for heads of state and other dignitaries, governing accepted behaviour in relations with other diplomatic representatives or over affairs of state.
   • 2009 September 19, Laura Johnson, “A mwah too far”, in The Guardian:

     Even the Queen (for whom the curtsey is a more standard address) was recently treated to an enthusiastic Obama embrace. Her Majesty, who is not normally known for partaking in such public displays of affection, seemed unperturbed by Michelle Obama's disregard for royal protocol.

9. (by extension) An accepted code of conduct; acceptable behaviour in a given situation or group.
   • 2010 July 16, The Guardian:

     For those uncertain in the protocol of handshaking a formula for the perfect handshake has been devised by scientists at the University of Manchester.

   • 2020 December 2, Paul Bigland, “My weirdest and wackiest Rover yet”, in Rail, page 66:

     TfW has staff enforcing mask protocols at all the busy stations and most travellers oblige, albeit some with ill grace.

10. (computing) A set of formal rules describing how to transmit or exchange data, especially across a network.
    • 2001, “More Shopping”, in Discosis, performed by Bran Van 3000 ft. Momus:

      Moloch passed the message to the Behemoth / Whose master passed it on to Zebedee / It was sent by Internet, by obscure protocols / To its recipient, the delicious Miss Gee

    • 2006, Zheng & Ni, Smart Phone and Next-Generation Mobile Computing, p. 444:

      An exception is Jabber, which is designed based on an open protocol called the extensible messaging and presence protocol (XMPP).

    • 2021 September 5, Eric Lipton, Ephrat Livni, “Crypto’s Rapid Move Into Banking Elicits Alarm in Washington”, in The New York Times‎, →ISSN:

      Founders of those kinds of platforms argue that they are just building a “protocol” ultimately led by a community of users, with the computer code effectively running the show.

11. (medicine) The set of instructions allowing a licensed medical professional to start, modify, or stop a medical or patient care order.
12. (Roman Catholicism) The introduction of a liturgical preface, immediately following the Sursum corda dialogue.
    • 2010, Virgilio T.J. Suerte Felipe, The Lord’s Supper, Eucharist, Mass… What’s in a Name? , →ISBN, pages 45–46:

      This protocol of the Preface has been constant, with minor modification, from the Apostolic Tradition, of Hippolytus in 215 A.D., the earliest extant text of the Eucharistic Prayer, to the present 2002 Missale Romanum.

    • 2011, Michael S. Driscoll, J. Michael Joncas, The Order of Mass: A Roman Missal Study Edition and Workbook, →ISBN, page 213:

      The proper Preface for Eucharistic Prayer II also appears as Common Preface VI. In it, the protocol and body of the Preface structure are meshed.