/ ˈmʌʃrʊm; NAmE ; -ruːm/ noun , verb
■ noun
a fungus with a round flat head and short stem . Many mushrooms can be eaten :
a field mushroom (= the most common type that is eaten, often just called a 'mushroom', and often grown to be sold)
fried mushrooms
cream of mushroom soup
—see also button mushroom , toadstool
■ verb [ v ]
1.
to rapidly grow or increase in number :
We expect the market to mushroom in the next two years.
2.
(usually go mushrooming ) to gather mushrooms in a field or wood
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WORD ORIGIN
late Middle English (originally denoting any fungus having a fleshy fruiting body): from Old French mousseron , from late Latin mussirio(n-) .