From Middle English muscheron, musseron, from Anglo-Norman musherum, moscheron, from Old French moisseron, of obscure origin: probably derived from Old French mosse, moise , as the use first applied to a type of fungus which grows in moss, from Frankish *mosu or odt *mosa, akin to Old High German mosa, Old High German mos, Old High German mios, Old English mēos, Old English mōs, Old Norse mosi, Old Norse myrr, from Proto-Germanic *musą, *musô, *miuziz, from Proto-Indo-European *mews-.

• (British, America) IPA: /ˈmʌʃˌɹuːm/, /ˈmʌʃˌɹʊm/

mushroom (plural mushrooms)

1. Any of the fleshy fruiting bodies of fungi typically produced above ground on soil or on their food sources (such as decaying wood).

   Synonyms: mushrump, shroom

   Some mushrooms are edible and taste good, while others are poisonous and taste foul.

2. A fungus producing such fruiting bodies.
3. Champignon or Agaricus bisporus, the mushroom species most commonly used in cooking.
4. Any of the mushroom-shaped pegs in bar billiards.
5. (architecture) A concrete column with a thickened portion at the top, used to support a slab.
6. (obsolete, figurative) One who rises suddenly from a low condition in life; an upstart.
   • 1627 (indicated as 1626), Francis [Bacon], “VI. Century.”, in Sylua Syluarum: Or A Naturall Historie. In Ten Centuries. […], London: […] William Rawley […]; [p]rinted by J[ohn] H[aviland] for William Lee […], →OCLC ↗:

     upstarts […] call in reproach mushrooms

7. (figurative) Something that grows very quickly or seems to appear suddenly.
8. Ellipsis of mushroom cloud

• French: champignon
• German: Pilz, Schwamm (Bavaria)
• Italian: fungo
• Portuguese: cogumelo
• Russian: гриб
• Spanish: hongo, seta

• German: Pilz
• Portuguese: fungo, cogumelo
• Russian: грибни́ца

mushroom (not comparable)

1. Having characteristics like those of a mushroom, for example in shape or appearance, speed of growth, or texture.

   mushroom cloud

• Portuguese: (em forma) de cogumelo
• Russian: грибови́дный

mushroom (mushrooms, present participle mushrooming; simple past and past participle mushroomed)

1. (intransitive, figurative) To grow quickly to a large size or rapidly increase in scope or scale.

   The town’s population mushroomed from 10,000 to 110,000 in five years.

2. (intransitive) To gather mushrooms.

   We used to go mushrooming in the forest every weekend.

3. (intransitive) To form the shape of a mushroom.
   • 2001, James E. Duffy, I-Car Professional Automotive Collision Repair, page 173:

     Excessive spot weld time may cause the electrode tips to mushroom, resulting in no focus of current and a weak weld.

   1. (ballistics, of a bullet) To form the shape of a mushroom when striking a soft target.

• French: champignonner
• German: wuchern
• Portuguese: estourar, explodir

• French: champignonner
• German: Pilze ernten, Pilze sammeln
• Portuguese: colher cogumelos