plural mushrooms
: a fungus that is shaped like an umbrella
wild mushrooms
especially
: one that can be eaten
cut up some mushrooms for the salad
—often used before another noun mushroom soup
a mushroom cap [=the top part of a mushroom]
mushrooms; mushroomed; mushrooming
1
: to increase or develop very quickly
The population has mushroomed [=shot up] over the past 10 years. = The town has mushroomed in population over the past 10 years.
Interest in local history is suddenly mushrooming.
Her hobby mushroomed into a thriving business.
2
: to collect wild mushrooms
He goes mushrooming in the spring every year.
Cite this Entry
“Mushroom.” Merriam-Webster.com Simple Definition, Merriam-Webster, https://www.merriam-webster.com/simple/mushroom. Accessed 15 Apr. 2026.
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