From Longman Dictionary of Contemporary Englishmushroommush‧room1 /ˈmʌʃruːm, -rʊm/ ●●● S3 noun [countable] 
DFone of several kinds of fungus with stems and round tops, some of which can be eaten → toadstool mushroom soup → magic mushroom
DFone of several kinds of fungus with stems and round tops, some of which can be eaten → toadstool mushroom soup → magic mushroomExamples from the Corpus
mushroom• mushroom soup• Place a cube of Gorgonzola atop each serving of polenta and mushrooms and warm under broiler.• Gibbs brought mushrooms for the fiesta.• Soak dried mushrooms in hot water to cover until soft, about 20 minutes.• He could have been right at that, when one considers the trips that hippies take after eating some types of mushroom.• Then other mushrooms began popping up.• If another living shaman eats a portion of shaman mushroom then it dissolves inside him and releases vast amounts of magic energy.• But atomic power to my generation always means that mushroom cloud.• His gaze moved along steadily until it rested on the mushrooms - chestnut mushrooms, shiitake mushrooms, field mushrooms.mushroommushroom2 verb [intransitive] GROW/GET BIGGERto grow and develop very quickly New housing developments mushroomed on the edge of town.→ See Verb tableExamples from the Corpus
mushroom• But indications are that growth is mushrooming.• So the risk from viruses certainly hasn't diminished - on the contrary, it has mushroomed.• The visible presence of corporate sponsorship has steadily mushroomed.• Countless travelers get similar surprises when flying both in the United States and abroad because of a mushrooming arrangement called code-sharing.• The problem for the future is the need to keep pace with mushrooming global population growth.• After all, it was her body that was about to mushroom, her life that was going to get derailed.• Bernstein's law practice had mushroomed in recent years.• Yet, despite the mushrooming of coffee bars in the high streets of western countries, supply still exceeds demand.• On the night interest had mushroomed to include several schools and colleges in the Lancaster area.From Longman Business Dictionarymushroommush‧room /ˈmʌʃruːm, -rʊm/ verb [intransitive] to develop very quicklyCable has mushroomed into a giant industry. —mushrooming adjectivethe mushrooming private business sector→ See Verb tableOrigin mushroom1 (1400-1500) French mousseron, from Latin mussirio 