Pylimitics

To ”ferment” something means to institute a biochemical process where carbon dioxide and alcohol are synthesized. Fermentation is a step in the creation of wine, vodka, whiskey, and the like. On the other hand, to ”foment” has to do with people; you might ”foment a dispute” or even ”foment rebellion” — that latter phrase is probably the most common way ”foment” is used.

The key ingredient in the fermentation process is yeast, so it’s no surprise that ”ferment” comes from the Latin word for yeast, ”fermentum.” Yeast-related processes were so well-known that the Latin word ”fermentare” means ”cause to rise,” which of course is what yeast does when you’re making bread. At least if you’re making it the right way.

”Foment” is also from Latin, in this case ”fomentum,” a soothing application or poultice. 

It’s just a coincidence that ”foment” and ”ferment” sound so similar, but it’s having an effect. If you look several definitions down from the first couple meanings for ”ferment” — not in all dictionaries, but in some — you’ll see the meaning for ”foment.” That’s because the words are so often confused that they’re beginning to share meanings as well as sounds. There isn’t any ”ferment-like” meaning listed for ”foment,” which suggests that when the two words are confused, ”ferment” is the one that tends to be used. And after all, you might make something of a case that ”fomenting a rebellion” is a little bit like fermentation, so why shouldn’t you be able to ”ferment a rebellion”? Or, of course, this being English, you have hundreds of thousands of words to choose from, so you might just say ”inciting,” ”encouraging,” or ”urging” that rebellion — but I’m not sure anybody exhorting, motivating, prompting, arousing, inflaming, or provoking civil unrest is particularly cognizant of vocabulary. 

If you were to start your fomenting on a train, you might start in the ”caboose.” That’s the last car in a freight train, and it’s a sort of mobile office (and sometimes living quarters) for the conductor and any staff. There are plenty of stories about fermentation being covertly practiced in cabooses, because back in the day some of the train staff had long periods with hardly anything to do. At one point, stopping a train meant that somebody had to climb from one car to another along the entire train and put the brakes of each individual car on. For that you needed people, but only once in a while. When they weren’t turning the brakes on or off, they’d hang out in the caboose. The term ”caboose” appeared in 1855 on a specific railroad: the Buffalo, Corning and New York.  Before the car was called a ”caboose,” it was a ”cabin car,” ”conductor’s van,” ”brakeman’s cab,” ”accommodation car,” ”way car,” or the somewhat pedestrian ”train car.” The word ”caboose” comes from ships originally; in both Dutch and German, the ”kabuse” was a ship’s galley or storeroom. Before that ”kabuse” meant ”shed” in German.

Possibly because the railroad managers wanted to give the workers something to do besides fomenting drunkenness by fermenting in the caboose, raised observation windows in the middle of the caboose were added  in 1860s. They were invented by T. B. Watson, who was a conductor on the Chicago and North Western Railway — not to foment confusion, but that railroad was neither in Chicago nor the northwest; it was located in Iowa. Maybe somebody was imbibing a bit too much of something fermented?