mushroom
1. [ noun ] a large cloud of rubble and dust shaped like a mushroom and rising into the sky after an explosion (especially of a nuclear bomb)
Synonyms: mushroom-shaped_cloud mushroom_cloud
Related terms: cloud
2. [ noun ] (botany) any of various fleshy fungi of the subdivision Basidiomycota consisting of a cap at the end of a stem arising from an underground mycelium
Related terms: basidiomycete morel
3. [ noun ] (botany) common name for an edible agaric (contrasting with the inedible toadstool)
Related terms: toadstool agaric
4. [ verb ] grow and spread fast
Examples:

"The problem mushroomed"

Related terms: grow
5. [ verb ] pick or gather mushrooms
Examples:

"We went mushrooming in the Fall"

Related terms: pick
6. [ noun ] (chemistry,food) fleshy body of any of numerous edible fungi
Related terms: vegetable stuffed_mushroom