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
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
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

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
At Wawona Hotel, mold and mushrooms were discovered growing in the ice machine in the employee break room, forcing the facility to be closed from April 2024 through the end of the year. Kathleen Wong, USA Today, 26 June 2025 Her mushroom blend is eyeballed, measured on instinct; Martin weighs and grinds and uses equipment, all while yelling and dancing crazily around the lab. Rafaela Bassili, Vulture, 25 June 2025
Verb
Their litany of injuries on the pitching side, particularly to the starting rotation, has mushroomed to cartoonish levels. Tony Blengino, Forbes.com, 10 June 2025 The time the two spent together in Los Angeles looking for work has mushroomed into show business lore, but another great story emerged when Kind stopped by for a visit with Steve Kmetko on his Still Here Hollywood podcast, which shed further insight into the relationship the two actors maintain. Jordan Hoffman, EW.com, 10 June 2025 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

Browse Nearby Words

Cite this Entry

“Mushroom.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/mushroom. Accessed 11 Jul. 2025.

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

mushroom

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

Medical Definition

mushroom

noun
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

More from Merriam-Webster on mushroom

Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!