Noun
1. common name for an edible agaric (contrasting with the inedible toadstool)
2. any of various fleshy fungi of the subdivision Basidiomycota consisting of a cap at the end of a stem arising from an underground mycelium
3. a large cloud of rubble and dust shaped like a mushroom and rising into the sky after an explosion (especially of a nuclear bomb)
4. fleshy body of any of numerous edible fungi