protocolyoudaoicibaDictYouDict[protocol 词源字典]
protocol: [16] Protocol originally denoted an ‘official record of a transaction’. Not until the end of the 19th century, as a reborrowing from French, did it come to be used for ‘rules of etiquette’ (the semantic link is an intermediate sense ‘draft of a treaty or other diplomatic document’, which led to its use in French for the ‘department in charge of diplomatic etiquette’). It goes back via Old French prothocole and medieval Latin prōtocollum to Greek prōtókollon, a compound formed from prótos ‘first’ and kólla ‘glue’ which meant ‘flyleaf glued to the front of a book giving a list of its contents’.
=> colloid[protocol etymology, protocol origin, 英语词源]
protocol (n.)youdaoicibaDictYouDict
1540s, as prothogall "draft of a document," from Middle French prothocole (c. 1200, Modern French protocole), from Medieval Latin protocollum "draft," literally "the first sheet of a volume" (on which contents and errata were written), from Greek protokollon "first sheet glued onto a manuscript," from protos "first" (see proto-) + kolla "glue."

Sense developed in Medieval Latin and French from "official account" to "official record of a transaction," to "diplomatic document," and finally, in French, to "formula of diplomatic etiquette." Meaning "diplomatic rules of etiquette" in English first recorded 1896, from French; general sense of "conventional proper conduct" is from 1952. "Protocols of the (Learned) Elders of Zion," Russian anti-Semitic forgery purporting to reveal Jewish plan for world domination, first published in English 1920 under title "The Jewish Peril."