mushroom

American  

[muhsh-room, -room] / ˈmʌʃ rum, -rʊm /

noun

1. any of various fleshy fungi including the toadstools, puffballs, coral fungi, morels, etc.

2. any of several edible species, especially of the family Agaricaceae, as Agaricus campestris meadow mushroom, or field mushroom, cultivated for food in the U.S.

3. anything of similar shape or correspondingly rapid growth.

4. a large, mushroom-shaped cloud of smoke or rubble, formed in the atmosphere as a result of an explosion, especially a nuclear explosion.

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adjective

1. of, consisting of, or containing mushrooms.

   a mushroom omelet.

2. resembling a mushroom in shape or form.

3. of rapid growth and often brief duration.

   mushroom towns of the gold-rush days.

verb (used without object)

1. to spread, grow, or develop quickly.

2. to gather mushrooms.

3. to have or assume the shape of a mushroom.

mushroom British  

/ -rʊm, ˈmʌʃruːm /

noun

1. 1. the fleshy spore-producing body of any of various basidiomycetous fungi, typically consisting of a cap (pileus) at the end of a stem arising from an underground mycelium. Some species, such as the field mushroom, are edible Compare pileus toadstool

   2. ( as modifier )

      mushroom soup

2. the fungus producing any of these structures

3. 1. something resembling a mushroom in shape or rapid growth

   2. ( as modifier )

      mushroom expansion

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verb

1. to grow rapidly

   demand mushroomed overnight

2. to assume a mushroom-like shape

3. to gather mushrooms

mushroom Scientific  

/ mŭsh′ro̅o̅m′ /

1. Any of various fungi that produce a fleshy fruiting body, which usually consists of a stalk topped by an umbrella-shaped cap. Many mushrooms are basidiomycetes. Some species of mushrooms are edible, though many are poisonous. The term mushroom is often applied to the stalk and cap alone.

2. See more at basidiomycete

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Other Word Forms

• mushroomlike
  adjective
• mushroomy
  adjective

Etymology

Origin of mushroom

First recorded in 1350–1400; alteration (by folk etymology) of Middle English muscheron, musseroun, from Middle French mousseron, ultimately from Late Latin mussiriōn-, stem of mussiriō

Explanation

A mushroom is the main body of a certain type of fungus. Edible mushrooms include portobellos and shiitakes. Don't mess around with the inedible types. Walk in the woods after a few days of rain, and you're sure to see mushrooms growing from the damp forest floor. Mushrooms like moist environments, and many mushrooms also grow incredibly fast, which is where the verb form of mushroom, "grow and spread quickly," comes from. The word's origin is ultimately uncertain, although some experts believe it's related to the French mousse, or "moss."

Example Sentences

California has seen an uptick in mushroom poisonings, with four people dying and 47 becoming seriously ill since November, according to the release.

From Los Angeles Times • May 15, 2026

California’s last major mushroom poisoning outbreak took place in 2016 with 14 reported cases, and while there were no deaths, three people required liver transplants and one child suffered permanent neurological damage.

From Los Angeles Times • May 15, 2026

Leclerc, who has spent more than 20 years mastering the art of the overtake since his days in go-karts, compared the whole thing to a videogame power-up: “This is like a mushroom in Mario Kart.”

From The Wall Street Journal • May 1, 2026

A quick mushroom sauce does the trick: earthy, glossy, just rich enough to make everything feel composed.

From Salon • Apr. 26, 2026

But it was all Clare could do to hide his patchy fur, his ear shriveled up like a dried mushroom, his missing left eye.

From "The Undead Fox of Deadwood Forest" by Aubrey Hartman

Related Words

• boom
• burgeon
• expand
• explode
• flourish
• proliferate
• shoot up