Where does “mushroom” come from?

Mushroom comes from Anglo-Norman musherum through Middle English musheron, with the original sense unknown.

mushroom (English): Any of the fleshy fruiting bodies of fungi...

Definitions

Step	Language	Word	Meaning
1	Middle English	muscheron	—
2	Anglo-Norman	musherum	—
3	Old French	moisseron	—
4	Old French	mosse	moss
5	Frankish	mosa	moss
6	Proto-Germanic	musą	moss, bog
7	Proto-Indo-European	mūs-	fly, stinging fly, gnat; moist, damp; swamp,...

mushroom — Etymology, Origin & Word History | Etymology Explorer