noun

1. 1. any of various rapidly growing, fleshy fungi, typically having a stalk capped with an umbrellalike top; esp., a gill or pore fungus
   2. the fruiting body of such a fungus
   3. an edible fruiting body of such a fungus
2. anything like a mushroom in shape or rapid growth

Etymology: ME muscheron < OFr moisseron < LL mussirio (gen. mussirionis)

adjective

1. of or made with mushrooms
2. like a mushroom in shape or rapid growth a mushroom cloud

intransitive verb

1. to hunt for and gather wild mushrooms
2. to grow or spread rapidly
3. to flatten out at the end so as to resemble a mushroom