protocol
/ˈprəʊtəkɒl/·프로토콜·noun
an official procedure, set of rules, or technical standard
GreekCEFR B2
Root
Greek 'protos' (first) + 'kolla' (glue)
Greek protokollon (first sheet glued to a manuscript) → Medieval Latin protocollum → French protocole → English protocol (15th c.)
In a word
Greek protos (first) + kolla (glue). From 'the glued first sheet of a document'. Medieval scribes glued a title sheet — bearing the heading and signatures — onto the body of a manuscript. That was protokollon. The word has changed clothes every age — medieval: first sheet of a charter → diplomacy: treaty protocol → medicine: care protocol → computing: communication protocol (HTTP, TCP). The 'https://' in your address bar is the same word as the glue-mark on a medieval scriptorium desk.
Examples
The hospital follows strict protocols.
HTTP is a protocol for the web.
Diplomats sign a protocol of agreement.
Related
protocoledproto-prototypeprotocolizationprotocolist