Toadstool has a very weird name, but an easy-to-guess etymology: it was just a fanciful name meant to poetically imply that mushrooms are furniture for amphibians. Mushroom, meanwhile, has a much more interesting and in-depth origin. At first blush, it may seem almost like it's a room for mushing things, but that's not right at all. The room part has nothing to do with rooms, and we won't be branching off into a portmanteau as we go back in time; that's just how the end of the word formed throughout the ages. Instead, we get to see a ton of phonetic changes. In Middle English, mushroom was spelled muscheron, musheron, and musseron; in Anglo-French and Old French it was musherun, meisseron, mousseron, and just mousse. At this point the word meant "moss" instead of "mushroom". Origin after this is uncertain, but it seems to get even more simplified as we travel to Low Frankish mosa, Proto-Germanic musa, and Proto-Indo-European meus (at this point it could also mean "mold" or "mildew"). Such an interesting origin for such a commonplace word!
Hello! I'm Adam Aleksic. This year, I graduated from Harvard University with a degree in Government and Linguistics. There, I co-founded the Harvard Undergraduate Linguistics Society and wrote a thesis on Serbo-Croatian language policy, magna cum laude. In addition to etymology, I also really enjoy philosophy, trivia, vexillology, geography, board games, conlanging, art history, and law.