Protocol was the 'first glued sheet' on a scroll, listing what's inside. Now: the official rules.
Prōtos (first) + kolla (glue). A prōtokollon was the first sheet glued to a papyrus roll, listing its contents and authority. It grew into 'official record', then 'official rules'.
The protocol for a Texas Aggie Muster or a Ranger ceremony: done exactly the same way every time.
Internet protocols like HTTP are agreed rules for how to talk. The word started as a 'first sheet' and grew into 'official rules'.
Practice it in Skepsis