Language Of Confusion: Writing Terms

Wow, I can’t believe I haven’t done some of these. Most of them I use every day!
 
First, let’s look at the most basic of what we use to make words: a letter. As a word, it first showed up in the thirteenth century, coming from the Old French letre. That’s then from the classical Latin littera, letter, and before that… no one knows. But its meaning really hasn’t changed much over the years. It meant a character that makes up words in Latin as well as a document. It really hasn’t changed at all.
 
Word comes from the Old English word, which means… word. No surprise there. It comes from the Proto Germanic wurda-, from the Proto Indo European were-, speak or say, which also happens to be the origin of verb. Kind of makes sense, right?
 
What do words make up? Phrases, of course. Also sentences, but we’ll get to that in a minute. Phrase is relatively recent, having shown up in the early sixteenth century. It comes from the Late Latin phrasis, diction, which is from the Greek phrasis, which is also just phrase. No one’s sure where that one came from, so I guess we can chalk this one up to the Greeks.
 
Now, sentence showed up in the thirteenth century, but then it meant either a judgment or a doctrine. It wasn’t until the late thirteenth century it meant understanding or wisdom, and from there it became the subject or content of a letter/book/speech. Then in the mid fifteenth century, it finally became what we generally use sentence to mean. The word comes from the Old French sentence and classical Latin sententia, sentence, from the verb sentire, which actually means to feel or sense. That’s actually the origin word for sense, meaning a sentence is really a sensation!
 
Next we’re looking at chapter. It showed up in the thirteenth century from the Old French chapitre. That’s from the Late Latin capitulum, which meant a chapter of a book or a synod (which is where we get the group division sense of the word). It’s a diminutive of the classical Latin caput, head, meaning the word means “little head”, and somehow we got a chapter from that. That word is also from the Proto Indo European kaput-, which means head, and is where we get kaput (as in dead or broken) from. As well as a bunch of other words, most of which with “cap” in them.
 
Finally today, book. It comes from the Old English boc, which was pronounced “book” and meant book. Stop me if I’m going too fast for you. Anyway, it’s thought to be from the Proto Germanic boko, from their word bokiz, beech. Yes, beech. It’s thought that book comes from the tree, beech. Possibly because runes were once inscribed on beechwood. I don’t even know what to make of that one.

 
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
Tony Jebson’s page on the Origins of Old English
Old English-English Dictionary
Orbis Latinus