Language Of Confusion: Flats, Part III

The next part of what is sure to be a ridiculously long series because just SO MANY words come from the Proto Indo European plat-, spread, and its root pele-, flat or to spread. This week: all sorts of plains. And planes.
 
First, plain showed up in the fourteenth century, coming from the Old French plain, and before that the classical Latin planus, flat, which is from pele-. In English, plain originally only meant flat, but it also started to mean “free from obstruction”, like flatland is, and it came to mean simple or unembellished. And that’s why we have plain. Also explain, which showed up in the fifteenth century. It’s from the classical Latin explanare, which means to comment on or, you know, explain, and is planus with ex-, out. To explain is to flatten out. Um, metaphorically, I have to assume. And now I’m sure you’re expecting me to go over complain. Nope. It’s not related to plain or explain. Seriously.

 
As for the other plane, it showed up in the seventeenth century, when it was decided they needed to differentiate the geometric sense of plane (which then also got used as part of airplane). It’s from the classical Latin planum, plane, which is from planus. Plan showed up in the late seventeenth century, first meaning a drawing, then a scheme, as it’s more commonly used today. It’s from the French plan, plan obviously, and that’s from planum. Because drawings were done on flat surfaces. Well, it makes more sense than explain does.
 
You know what looks like plane? Planet. You know what’s in all likelihood not related to plane? Also planet. So no, we won’t be looking at it. Instead, we’re looking at place. It’s the oldest word here, having shown up in the thirteenth century, coming from the Old French place and Medieval Latin placea. That’s from the classical Latin platea, which meant street or courtyard or an open space. It’s from the Greek plateia, a square or plaza, which is from platys, wide or broad. A word we covered extensively last week.
 
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