When researching my post on coddle, I found that something else that's unexpected derives from the Proto-Indo-European word for "heat", kele. I guess you'll just have to read on to find out what! Kele later became the Proto-Italic root kaleo, also "heat", and we venture out of the realm of reconstruction as the history of the word develops on to calere, the verb form of all this, meaning "to be warm". Added to the verb facere ("to do"), this became calefacere, or "to make something warm". After some international mangling, calefacere became chaufer in Old French, still with the same definition. This retained its spelling for a while, until it became chauffeur. More time passed, and then the Industrial Revolution happened. Engines arrived, and the French needed a name for them. They chose chauffeur because engines heat up with use. Soon, chauffeur became metonymically applied to the people who use them. Now with the definition of "motorist", it's not hard to see why chaffeur means what it does today.
Adam Aleksic is a sophomore studying linguistics and government at Harvard University. He also has disturbing interests in politics, vexillology, geography, board games, conlanging, and law.