psilocybin

noun

psi·​lo·​cy·​bin ˌsī-lə-ˈsī-bən 

: a hallucinogenic indole C₁₂H₁₇N₂O₄P obtained from a fungus (such as Psilocybe mexicana or P. cubensis synonym Stropharia cubensis)

Examples of psilocybin in a Sentence

Recent Examples on the Web

Additionally, life-extending and anti-aging effects were observed in older mice treated with psilocybin. —Ruairi MacKenzie, Discover Magazine, 16 July 2025

As was what psilocybin pioneer Paul Stamets had to say. —Ramon Ramirez, Austin American Statesman, 2 July 2025

Half received psilocybin at the beginning of the trial, and the other half received the treatment eight weeks later. —Khloe Quill, FOXNews.com, 24 June 2025

Other psychedelics, such as psilocybin and MDMA, also have this designation. —Amber X. Chen, Smithsonian Magazine, 18 June 2025

Word History

Etymology

New Latin Psilocybe, fungus genus + -in entry 1

First Known Use

1958, in the meaning defined above

Kids Definition

psilocybin

noun

psi·​lo·​cy·​bin ˌsī-lə-ˈsī-bən 

: a chemical that is obtained from a fungus and causes hallucinations

Medical Definition

psilocybin

noun

psi·​lo·​cy·​bin ˌsī-lə-ˈsī-bən 

: a hallucinogenic indole C₁₂H₁₇N₂O₄P obtained from a basidiomycetous fungus (as Psilocybe mexicana or P. cubensis synonym Stropharia cubensis)