mushroom

MUSH-room/ˈmʌʃˌɹuːm/

Pluralmushrooms

Verbmushrooms, mushrooming, mushroomed

11 meanings of mushroom

Practice

1
nouncountable
A fungus with a fleshy, usually capped and stalked fruiting body that grows above ground, or that fruiting body itself; many kinds are edible.
The mushroom pushed up through the damp soil overnight.
Several mushrooms had sprouted along the rotting log.
Similarfungus, toadstool
2
common cooking kindnouncountable
The common edible species Agaricus bisporus, the kind most often used in cooking.
She stuffed each mushroom with breadcrumbs and fresh herbs.
The recipe calls for a cup of finely chopped mushrooms.
3
fungus-shapedadjectivebefore a noun
Resembling a mushroom in some way, such as in shape, appearance, rapid growth, or texture.
The architect favored a mushroom silhouette for the plaza canopy.
The park has a mushroom fountain, with water spilling over its wide, round top.
UsageGoes before a noun: a mushroom cloud. After a verb, for shape, say mushroom-shaped.
4
expand quicklyverbfigurativelyintransitive
To grow quickly to a large size, or to increase rapidly in scope or scale.
Like a snowball rolling downhill, growing larger with every turn.
Demand for the app mushroomed within weeks of its launch.
Cities tend to mushroom when a new industry arrives.
Similarboom, explode, burgeon, balloon, skyrocket
Oppositeshrink, dwindle, decline
Note
Growth figures are where this verb lives: populations, enterprises, platforms and fortunes all mushroom. Thomas L. Friedman uses it in 2021 of social media platforms.
Checked 2 Nov 2026 · 1 fact
Wiktionary attributes this use about social media platforms to Thomas L. Friedman in 2021. en.wiktionary.org

Less common meanings

5
explosion cloudnounabbreviationellipsis
Short for mushroom cloud: the mushroom-shaped cloud of smoke and debris that rises after a very large explosion, especially a nuclear one.
The test sent a towering mushroom above the atoll.
Cameras captured the mushroom spreading against the dawn sky.
UsageUse mushroom cloud when the cloud meaning is not clear from context.
6
pick wild fungiverbintransitive
To gather wild mushrooms, usually from woods or fields.
Like foraging for berries, but hunting for fungi instead.
When we went mushrooming in the hills, my grandparents showed us which ones were safe to eat.
On cool autumn weekends, she goes mushrooming in the state forest near her cabin.
UsageMostly in go mushrooming, like go fishing; use for before a specific kind: go mushrooming for chanterelles.
Similarforage
7
verbintransitive
To spread out at the top or tip into a mushroom shape, as a rivet head when hammered or a bullet on striking a target.
Like a column of smoke flattening and spreading as it rises.
The rivet head mushroomed as the hammer struck it repeatedly.
Soft lead tends to mushroom when pressed against a hard surface.
Similarspread, flatten, splay
Note
This is a workshop word for metal that spreads out under repeated force or heat, such as rivet heads or electrode tips. James E. Duffy, in a textbook on collision repair, warns that too long a spot-weld time makes electrode tips mushroom. The current then loses its focus and the weld comes out weak. In this setting, mushrooming is usually wear to watch for rather than a goal.
Checked 31 Oct 2026 · 4 facts
Rivet heads can be formed into a mushroom shape by hammering. seecs.ctevt.org.np
Spot-welding electrode tips mushroom through repeated heating. prospot.shop
James E. Duffy's collision-repair textbook warns that excessive spot-welding time can mushroom electrode tips, dispersing the current and producing a weak weld. en.wiktionary.org
Electrode mushrooming is deterioration requiring corrective maintenance. tjsnow.com
8
social climbernounobsoletefiguratively
A person who rises suddenly from humble beginnings to wealth or status; an upstart.
Like someone who wins the lottery and suddenly moves into a mansion.
The duchess refused to receive such a mushroom at her table.
These newly rich mushrooms had neither land nor lineage to recommend them.
Note
An old insult drawn from how suddenly mushrooms appear. Francis Bacon, in Sylva Sylvarum (1626), notes that upstarts are called mushrooms "in reproach." The word carried scorn for people who had risen suddenly in rank or wealth.
9
noundated
A thing that grows very quickly or seems to spring up all at once.
The craze [hula hoops] began in the U.S.A., and in October the boom crossed the Atlantic and 40 firms sprang into being, some being overnight mushrooms.
1971, Gwen White, Antique Toys And Their Background
10
noun
A concrete column whose top is enlarged so that it can bear a slab above it.
11
noun
Any of the mushroom-shaped pegs in the game of bar billiards.

Practice

Can you tell the meanings of mushroom apart? Answer 3 quick questions from this page, or write your own sentence and AI will check it.

Origin

The word came into Middle English as muscheron from Anglo-Norman and Old French, of obscure origin. It probably derives from Old French mosse or moise ("moss"), since the name was first applied to a fungus that grows in moss; alternatively the Old French form may be of pre-Roman origin. It is a doublet of moss and mousse.

Checked 31 Oct 2026 · 5 facts

Mushroom comes through Middle English muscheron from Anglo-Norman and Old French. en.wiktionary.org
The ultimate origin is obscure. en.wiktionary.org
The proposed derivation is from Old French words meaning moss, referring originally to a fungus growing in moss. en.wiktionary.org
A pre-Roman origin for the Old French form is an alternative explanation. en.wiktionary.org
Mushroom is a doublet of moss and mousse. en.wiktionary.org