mushroom

1 of 2

noun

mush·​room ˈməsh-ˌrüm How to pronounce mushroom (audio)
-ˌru̇m;
chiefly Northern and Midland US -ˌrün;
dialectal ˈmə-shə-ˌrüm, 
-ˌru̇m, 
-ˌrün
Synonyms of mushroomnext
1
a
: an enlarged complex aboveground fleshy fruiting body of a fungus (such as a basidiomycete) that consists typically of a stem bearing a pileus
especially : one that is edible
b
: fungus
2
: upstart
3
: something resembling a mushroom

mushroom

2 of 2

verb

mushroomed; mushrooming; mushrooms

intransitive verb

1
a
: to well up and spread out laterally from a central source
b
: to become enlarged or extended : grow
2
: to collect wild mushrooms
3
: to spring up suddenly or multiply rapidly

Synonyms of mushroom

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Verb

See All Synonyms & Antonyms in Thesaurus

Examples of mushroom in a Sentence

Noun cut up some mushrooms for the salad Verb Interest in local history is suddenly mushrooming. Her hobby mushroomed into a thriving business. He goes mushrooming in the spring every year.
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Noun
Matt Kirouac, the author of the ramen ranking on Tasting Table, highlighted the restaurant’s mushroom paitan ramen, complementing its cashew cream, shimeji mushrooms and pork belly. — Emma Hall, Sacbee.com, 28 Aug. 2026 Its first sessions will include a September program with mushroom spawn producer Sylvan Biotech and an intellectual-property workshop in October. — Alexandra Harrell, Footwear News, 27 Aug. 2026
Verb
When Oprah Winfrey featured the author and his book on her podcast, things mushroomed. — Mike Fleming Jr, Deadline, 19 Aug. 2026 Davis has previously alleged that, amid mushrooming violence between the two groups, Combs had offered Davis a bounty on the lives of his rivals, Knight and Shakur. — Sasha Pezenik, ABC News, 17 Aug. 2026 See All Example Sentences for mushroom

Word History

Etymology

Noun

Middle English musheron, from Anglo-French musherum, musseron, from Late Latin mussirion-, mussirio

First Known Use

Noun

15th century, in the meaning defined at sense 1a

Verb

1893, in the meaning defined at sense 1a

Time Traveler
The first known use of mushroom was in the 15th century

Phrases Containing mushroom

Browse Nearby Words

mushrebiyeh
mushroom
mushroom anchor
See all Nearby Words

Cite this Entry

“Mushroom.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/mushroom. Accessed 1 Sep. 2026.

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Kids Definition

mushroom

1 of 2 noun
mush·​room ˈməsh-ˌrüm How to pronounce mushroom (audio)
-ˌru̇m
1
: a fleshy part of a fungus that bears spores, grows above ground, and consists usually of a stem bearing a flattened cap
especially : one that is edible
2
: fungus sense 1

mushroom

2 of 2 verb
: to appear or develop suddenly or increase rapidly
the population mushroomed

Medical Definition

mushroom

noun
mush·​room ˈməsh-ˌrüm How to pronounce mushroom (audio) -ˌru̇m How to pronounce mushroom (audio)
1
: an enlarged complex fleshy fruiting body of a fungus (as most basidiomycetes) that arises from an underground mycelium and consists typically of a stem bearing a spore-bearing structure
especially : one that is edible compare toadstool
2
: fungus sense 1

More from Merriam-Webster on mushroom

Britannica.com: Encyclopedia article about mushroom

Last Updated: - Updated example sentences
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