coleslaw
One day I made an etymological connection that was both surprising and very obvious: that the first syllable of coleslaw was clearly related to our word kale, as kale is a variety of cabbage and coleslaw is made from cabbage. The connections did not end there: a variation of that same syllable also appears in the words cauliflower, kohlrabi and collard greens, although curiously the middle syllable in broccoli is unrelated, even if the broccoli plant itself belongs to the same family. (Broccoli is a diminutive of the Italian brocco, “shoot, nail or tooth,” which in turn comes from the Latin broccus, which also gives us brooch.)
On its own, cole just means cabbage, and it comes through Middle English from the Latin caulis, “stem, stalk,” which Etymonline notes became the Vulgar Latin word for “cabbage,” replacing brassica, which still exists as in various biological names for cabbages. (Brassica oleracea is the species that includes all the edible plants I mention in the previous paragraph, plus Brussels sprouts, savoy cabbage, and gai lan. There is also the family Brassicaceae, which includes rocket, arugula, cresses, radishes, horseradish wasabi and mustards.) And caulis goes back to the Proto Indo-European root *(s)kehuli-, “stem of a plant, stalk,” which also gives us the Old Irish cual “faggot, bundle of sticks,” the Greek kaulos, “stem, stalk, pole,” the Armenian c’awl, “stalk, straw,” and the Lithuanian káulas, “bone.”
What’s interesting about cauliflower is that it goes back to the Italian cavolo fiori, “flowered cabbage,” with cavolo being the singular Italian word for “cabbage.” And cavolo and cabbage are close enough — and often when moving through history from one language to the next, Bs become Ps, and Ps become Fs, and Fs, become Vs, to the point that you could imagine that cavolo and cabbage were themselves related, but again that’s apparently no the case: cabbage comes to English from an Old French word for “head,” for obvious reasons.
The second part of kohlrabi comes from the Old French rape, which in turn goes back to the Latin rapa, rapum, “turnip.” The species Brassica rapa includes not only turnips but also napa cabbage (a.k.a. Chinese cabbage), bomdong, bokchoy and rapini. Confusingly, the similarly named Brassica napus is rapeseed, a different but related plant, from which we get rapeseed oil and, from one cultivar, canola oil. According to Wikipedia, the first syllable in canola comes from Canada, where it was first trademarked, and then the -ola ending in this case specifically stands for “oil, low acid,” Shinola similarities notwithstanding.