Protocol
Protocol may refer to:

Sociology and politics
Protocol (politics), a formal agreement between nation states
Protocol (diplomacy), the etiquette of diplomacy and affairs of state
Etiquette, a code of personal behavior

Science and technology
Protocol (science), a predefined written procedural method of conducting experiments
Medical protocol (disambiguation)

Computing
Protocol (object-oriented programming), a common means for unrelated objects to communicate with each other (sometimes also called interfaces)
Communication protocol, a defined set of rules and regulations that determine how data is transmitted in telecommunications and computer networking
Cryptographic protocol, a protocol for encrypting messages
Decentralized network protocol, a protocol for operation of an open source peer-to-peer network where no single entity nor colluding group controls a majority of the network nodes

Music
Protocol (album), by Simon Phillips
Protocol (band), a British band
"Protocol", a song by Gordon Lightfoot from the album Summertime Dream
"Protocol", a song by the Vamps from their 2020 album Cherry Blossom

Other uses
Protocol (film), a 1984 comedy film
Protocol (website), an offshoot of Politico
Minutes, also known as protocols, the written record of a meeting
Protocol, a news website owned by Capitol News Company

See also
Proprietary protocol, a communications protocol owned by a single organization or individual
Proto (disambiguation)
Quantum cryptography protocol, a protocol for encrypting messages
The Protocols of the Elders of Zion, a notorious antisemitic hoax that has circulated since the early 20th century