fly agaric

noun

: a medium to large poisonous amanita mushroom (Amanita muscaria) with a usually bright red cap

Examples of fly agaric in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Among the more celebrated examples of this phenomenon are Siberian reindeer, which partake in the consumption of the fly agaric mushroom, a hallucogenic. Gary Laderman, Fortune Well, 17 July 2023 Meanwhile, muscimol, the active ingredient in the Amanita muscaria, or fly agaric fungus, so well attested in traditional religious practices throughout Eurasia, is legal in 49 states, and common, alongside cannabis, in the dispensaries of New York. Justin E. H. Smith, WIRED, 7 Mar. 2023

Word History

First Known Use

1788, in the meaning defined above

Time Traveler
The first known use of fly agaric was in 1788

Browse Nearby Words

Cite this Entry

“Fly agaric.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/fly%20agaric. Accessed 11 Aug. 2025.

Medical Definition

fly agaric

noun
: a poisonous mushroom of the genus Amanita (A. muscaria) that has a variably colored but typically bright-red pileus with a warty white scurf on the surface that with the related death cap is responsible for most cases of severe mushroom poisoning, that has been used as a source of poison for flypaper, and that is extensively used chiefly in northeastern Asia as an intoxicant especially for the hallucinatory effects that it produces

called also fly amanita, fly mushroom

More from Merriam-Webster on fly agaric

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!