mushroom

Etymology

From Middle English muscheron, musseron, from Anglo-Norman musherum, moscheron, from Old French moisseron, of obscure origin: probably derived from Old French mosse, moise ("moss"; whence also French mousse), as the use first applied to a type of fungus which grows in moss, from Frankish *mosu (“moss”) or Old Dutch *mosa (“moss”), akin to Old High German mosa (“moor, swamp”), Old High German mos (“moss, bog”), Old High German mios (“moss, mire”), Old English mēos (“moss”), Old English mōs (“bog, marsh”), Old Norse mosi (“moss”), Old Norse myrr (“bog, mire”), from Proto-Germanic *musą, *musô, *miuziz (“mosses, bog”), from Proto-Indo-European *mews- (“mosses, mold, mildew”). Displaced native Old English swamm. More at mire. Alternatively, the Old French may be of pre-Roman origin. See Ancient Greek μύκης (múkēs, “mushroom”). Doublet of moss and mousse

noun

1. Any of the fleshy fruiting bodies of fungi typically produced above ground on soil or on their food sources (such as decaying wood).
   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.
7. (figurative) Something that grows very quickly or seems to appear suddenly.
8. Ellipsis of mushroom cloud.

adj

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

verb

1. (intransitive, figurative) To grow quickly to a large size.
   The town’s population mushroomed from 10,000 to 110,000 in five years.
   The world's population of ultra-high-net-worth individuals, a super-elite with assets of at least $30m, has now mushroomed beyond 250,000 people, all in need of somewhere to store their wealth. 1 June 2019, Oliver Wainwright, “Super-tall, super-skinny, super-expensive: the ‘pencil towers’ of New York’s super-rich”, in Katharine Viner, editor, The Guardian, London: Guardian News & Media, →ISSN, →OCLC, archived from the original on 2020-10-05
   It has its own global news gathering and sharing platforms, like Facebook, YouTube and Twitter. […] In recent years, all these platforms have mushroomed. 2021-02-10, Thomas L. Friedman, “Cyberspace Plus Trump Almost Killed Our Democracy. Can Europe Save Us?”, in The New York Times, →ISSN
2. To gather mushrooms.
   We used to go mushrooming in the forest every weekend.
3. To form the shape of a mushroom.
   Excessive spot weld time may cause the electrode tips to mushroom, resulting in no focus of current and a weak weld. 2001, James E. Duffy, I-Car Professional Automotive Collision Repair, page 173
   1. (ballistics, of a bullet) To form the shape of a mushroom when striking a soft target.