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

The lead author, Roland Griffiths, gave three dozen healthy adults with no history of drug use a large dose of psilocybin. — Claire Hoffman, Rolling Stone, 21 Sep. 2026

Days after the executive order, the FDA issued national priority vouchers to companies studying psilocybin for treatment-resistant depression and major depressive disorder and metylone for post-traumatic stress disorder. — Brenda Goodman, CNN Money, 21 Sep. 2026

This means that psilocybin use could benefit a wide range of patients at different stages of cancer. — Rachel Raposas, PEOPLE, 7 Sep. 2026

The results, published on Thursday in the journal Science, show that mice that were given two doses of psilocybin were protected against nerve damage caused by chemotherapy for as many as six cycles of treatment. — Jackie Flynn Mogensen, Scientific American, 3 Sep. 2026

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)