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

Andrey Lopez is facing eight charges related to selling, possessing and delivering drugs, including marijuana, psilocybin and an opioid, his arrest report read. —Devoun Cetoute, Miami Herald, 14 Mar. 2026

David Nichols, a neuroscientist who is an expert on psychedelics, told me about a woman with alcohol-use disorder who realized during a psilocybin trip that her drinking was harming her children and decided to stop. —Clayton Dalton, New Yorker, 13 Mar. 2026

The attorney general's office said officials seized 1,200 fentanyl pills, 15 bricks of fentanyl, 13 grams of raw fentanyl, 300 grams of crack cocaine, 16 grams of psilocybin mushrooms and 450 grams of marijuana. —Madeline Bartos, CBS News, 10 Mar. 2026

At the end of six months, those who had taken just one dose of psilocybin had more than six times greater odds of being abstinent from cigarettes than their counterparts who relied on the nicotine substitute. —Will Stone, NPR, 10 Mar. 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)