Language Of Confusion: Per-, Part III

Once again, we’re looking at the words descended from the Proto Indo European per-, forward. Now that we have the prefixes out of the way, we can look at some of the words that grew out of them.
 
First, protocol. It showed up in the mid fifteenth century (also spelled prothogol and prothogall), from the French prothocole and Medieval Latin protocollum, and guess what? Back then it meant prologue, then a draft of a document, the minutes of a meeting, rough draft, diplomatic document, and finally in French, the “formula of diplomatic etiquette”. Which English picked up for use in 1896, and not really meaning proper conduct until 1952. Anyway, that protocollum comes from the Greek protokollon, with the proto- from the prefix meaning first, and the rest from kolla, which means… glue. Yeah, protocol is “first glue”.
 
Next, prone showed up in the fifteenth century, from the classical Latin pronus, which figuratively means prone and literally means bent forward. And that’s believed to be taken from the pro- prefix, which means forward. Being prone is being bent towards something. Sometimes literally!
 
A little more surprising is approach. It showed up in the fourteenth century from the Anglo French approcher, Old French aprochier, and Late Latin appropiare. The a- prefix is from ad, to, and the rest is from propiare, come nearer, related to the classical Latin prope. Prope is then from the PIE propro, even further, and that’s from per-, forward. To approach is to get nearer to. Rapprochement is actually from the same place. It showed up in 1809, from the French rapprochement, where the re- means back or again and the rest is the abovementioned aprochier. Rapprochement is near again… ment.
 
Reproach is weirdly different. It showed up in the mid fourteenth century from the Anglo French repruce, Old French reproche, and its verb form reprochier, which looks quite similar to the approach one. One possibility is that’s from the Vulgar Latin repropiare, with the re- meaning opposite of, and the rest from prope, near, which doesn’t quite make sense (this is etymology after all). Another theory is that it’s related to the classical Latin reprobus/reprobare, to reject, with the probare being the origin word of prove. And what word did we start this whole series with? Yes, so either way, reproach is from per-.
 
Sources
Online Etymology Dictionary
Google Translate
Omniglot
University of Texas at Austin Linguistic Research Center
University of Texas at San Antonio’s page on Proto Indo European language
Dictionary of Medieval Latin
Encyclopaedia Britannica
Fordham University
Orbis Latinus