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

• accelerate
• accumulate
• appreciate
• balloon
• boom
• build up
• burgeon
• bourgeon
• climb
• enlarge
• escalate
• expand
• gain
• increase
• mount
• multiply
• proliferate
• rise
• roll up
• snowball
• spread
• swell
• wax

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

Vegetables like broccoli, tomatoes, mushrooms, onions, kale and asparagus are also included in most low-carb diets—as are eggs, cheese, Greek yogurt and nuts like walnuts, peanuts, macadamia nuts and pistachios. —Daryl Austin, USA Today, 29 Mar. 2025

The bartenders shake up unconventional cocktails that use ingredients like tofu, mushroom, and peppercorn. —Taylor McIntyre, Travel + Leisure, 28 Mar. 2025

Verb

The West Facility started as the communicable disease facility, but has since mushroomed into a hodgepodge of ailing people, difficult to handle detainees and a number of dorm units that were recently expanded. —Kerry Burke, New York Daily News, 20 Mar. 2025

Yet Trump has a unique hold on his base, and threats of primaries in cases of disloyalty may be a permanent fixture for lawmakers to prevent opposition to Cabinet picks to mushroom over the next several weeks -- and to enforce support over next four years. —Tal Axelrod, ABC News, 10 Dec. 2024

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