Not all mushrooms are toadstools, only the ones that’ll kill you.
And that’s where the name comes from. The German word for poisonous mushrooms is todesstuhl, meaning “death’s stool.”
English speakers heard “toad stool,” and this botched translation stuck.
Since many mushrooms do resemble little chairs, it wasn’t too hard to imagine little forest toads taking a quick sit-down on one of them on their way through the woods.
Take note, however, there is no clear distinction between mushrooms are toadstools as the terms were never precisely defined.
The word “mushroom” and other variations may have been derived from the French word mousseron in reference to moss.