Try Our Apps


Avoid these words. Seriously.


[muhsh-room, -roo m] /ˈmʌʃ rum, -rʊm/
any of various fleshy fungi including the toadstools, puffballs, coral fungi, morels, etc.
any of several edible species, especially of the family Agaricaceae, as Agaricus campestris (meadow mushroom or field mushroom) cultivated for food in the U.S.
anything of similar shape or correspondingly rapid growth.
a large, mushroom-shaped cloud of smoke or rubble, formed in the atmosphere as a result of an explosion, especially a nuclear explosion.
of, consisting of, or containing mushrooms:
a mushroom omelet.
resembling a mushroom in shape or form.
of rapid growth and often brief duration:
mushroom towns of the gold-rush days.
verb (used without object)
to spread, grow, or develop quickly.
to gather mushrooms.
to have or assume the shape of a mushroom.
Origin of mushroom
1350-1400; alteration (by folk etymology) of Middle English muscheron, musseroun < Middle French mousseronLate Latin mussiriōn-, stem of mussiriō
Related forms
mushroomlike, adjective
mushroomy, adjective Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2018.
Cite This Source
Examples from the Web for mushrooming
Historical Examples
  • Twelve years ago the neighbourhood had shown no signs of mushrooming into its present opulence.

    Gigolo Edna Ferber
  • There were nutting and blackberrying and mushrooming and May-daying—plenty of simple merrymakings—within reach of all.

    The Retrospect

    Ada Cambridge
  • The cliffs resembled castle walls rising from the buried city, mushrooming themselves into sudden arrogance.

    The Three Sapphires W. A. Fraser
  • mushrooming where it had struck Johnny and then the tree, the slug still retained its shape where it had fitted its brass shell.

    Trading Jeff and his Dog James Arthur Kjelgaard
  • Close at hand, one of the lava-needles vanished in soundless display of mushrooming explosion.

    Master of the Moondog Stanley Mullen
  • It had been made by a mushrooming bullet, and the wonder was that the man had lived at all after receiving it.

    Louisiana Lou William West Winter
British Dictionary definitions for mushrooming


/ˈmʌʃruːm; -rʊm/
  1. the fleshy spore-producing body of any of various basidiomycetous fungi, typically consisting of a cap (pileus) at the end of a stem arising from an underground mycelium. Some species, such as the field mushroom, are edible Compare pileus, toadstool
  2. (as modifier): mushroom soup
the fungus producing any of these structures
  1. something resembling a mushroom in shape or rapid growth
  2. (as modifier): mushroom expansion
verb (intransitive)
to grow rapidly: demand mushroomed overnight
to assume a mushroom-like shape
to gather mushrooms
Word Origin
C15: from Old French mousseron, from Late Latin mussiriō, of obscure origin
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Cite This Source
Word Origin and History for mushrooming



mid-15c., muscheron, musseroun (attested 1327 as a surname, John Mussheron), from Anglo-French musherun, Old French meisseron (11c., Modern French mousseron), perhaps from Late Latin mussirionem (nominative mussirio), though this might as well be borrowed from French. Barnhart says "of uncertain origin." Klein calls it "a word of pre-Latin origin, used in the North of France;" OED says it usually is held to be a derivative of French mousse "moss" (from Germanic), and Weekley agrees, saying it is properly "applied to variety which grows in moss," but Klein says they have "nothing in common." For the final -m Weekley refers to grogram, vellum, venom. Modern spelling is from 1560s.

Used figuratively for something or someone that makes a sudden appearance in full form from 1590s. In reference to the shape of clouds after explosions, etc., it is attested from 1916, though the actual phrase mushroom cloud does not appear until 1955.



"expand or increase rapidly," 1741, from mushroom (n.). Related: Mushroomed; mushrooming.

Online Etymology Dictionary, © 2010 Douglas Harper
Cite This Source
mushrooming in Science

Any of various basidiomycete fungi whose mycelium produces a spore-dispersing body (called a basidioma) that usually consists of a stalk topped by a fleshy, often umbrella-shaped cap. Some species of mushrooms are edible, though many are poisonous. The term mushroom is often applied to the stalk and cap alone. See more at basidiomycete.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
Cite This Source
Slang definitions & phrases for mushrooming



  1. A person who is deliberately kept ignorant and misinformed
  2. : The growing contempt for accidental victims is even indicated by the name killers give them: ''mushrooms'' who ''pop up'' in the line of fire (late 1980s+)
The Dictionary of American Slang, Fourth Edition by Barbara Ann Kipfer, PhD. and Robert L. Chapman, Ph.D.
Copyright (C) 2007 by HarperCollins Publishers.
Cite This Source

Word of the Day

Nearby words for mushrooming

Difficulty index for mushroom

Most English speakers likely know this word

Word Value for mushrooming

Scrabble Words With Friends