n. & v.
1. the usu. edible spore-producing body of various fungi, esp. Agaricus campestris, with a stem and domed cap, proverbial for its rapid growth.
2 the pinkish-brown colour of this.
3 any item resembling a mushroom in shape (darning mushroom).
4 (usu. attrib.) something that appears or develops suddenly or is ephemeral; an upstart.
1. appear or develop rapidly.
2 expand and flatten like a mushroom cap.
3 gather mushrooms.
Phrases and idioms:
mushroom cloud a cloud suggesting the shape of a mushroom, esp. from a nuclear explosion. mushroom growth 1 a sudden development or expansion.
2 anything undergoing this.
Etymology: ME f. OF mousseron f. LL mussirio -onis