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

Increasing adverse effects The explosion of nootropic mushroom products has led to a wide variety of products on the market that potentially contain wildly differing levels of mushrooms, many times containing blends of multiple mushroom species. —Joshua Kellogg, The Conversation, 15 Aug. 2025

There's some evidence that eating mushrooms can improve your overall cholesterol profile and lower your average blood pressure.7 Dark, leafy green vegetables like spinach are great for your health. —Sarah Bence, Verywell Health, 13 Aug. 2025

Verb

The Lone Star State amounts to the first battle in a mushrooming national redistricting battle that Trump unleashed last month with the goal of helping Republicans hold onto control of Congress next year, when history says the sitting president’s party would be expected to lose ground. —Dave Goldiner, New York Daily News, 20 Aug. 2025

That would set off a mushrooming scramble of other statewide officeholders who were down the food chain to forgo reelection for a chance to win a higher prize. —John C. Moritz, Austin American Statesman, 30 July 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