mushroom

1 of 2

noun

mush·​room ˈməsh-ˌrüm 

-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

: 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

Verb

• increase
• rise
• swell
• accelerate
• wax
• expand
• climb

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

Noun

Start with a glass of stout and the Hungarian mushroom soup before moving on to either the pork shank, prime rib (the best in town) or Amish chicken for an entree. —Keith Pandolfi, Cincinnati Enquirer, 24 Oct. 2025

There are mushrooms growing from the walls. —David Wingrave, Harpers Magazine, 24 Oct. 2025

Verb

Brands that were once skeptical about influencers have embraced them over time as sales-tracking tools have improved and the fan base of video creators has mushroomed. —Tribune News Service, San Diego Union-Tribune, 22 Oct. 2025

Branches of major restaurant and store chains have mushroomed around the center in recent years, and the local mall has become a regional go-to, so much so that Apple massively expanded its store there earlier this year. —Ivana Kottasová, CNN Money, 4 Oct. 2025

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

Phrases Containing mushroom

• button mushroom
• chaga mushroom
• chicken mushroom
• enokidake mushroom
• enoki mushroom
• enokitake mushroom
• field mushroom
• lion's mane mushroom
• magic mushroom
• meadow mushroom
• mushroom cap
• mushroom cloud
• oyster mushroom
• sacred mushroom
• straw mushroom
• sulfur mushroom

Kids Definition

mushroom

1 of 2 noun

mush·​room ˈməsh-ˌrüm 

-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  -ˌru̇m 

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