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 of mushroom

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

In accordance with the folkways of my rough generational cohort, someone had brought chocolates studded with small doses of hallucinogenic mushrooms. — Vinson Cunningham, New Yorker, 23 Aug. 2026

Now, researchers are trying to find an option that checks all the boxes, and the best material for it seems to be … mushrooms. — Maryna Holovnova, New Atlas, 22 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

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