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 Natural Medicine Act, which decriminalized psilocybin and greenlit the state's development of a therapeutic pathway for mushrooms, also decriminalized ibogaine and other psychedelics. —Olivia Young, CBS News, 24 Apr. 2026

The benefits of ibogaine were more pronounced than those that had been previously reported with psilocybin, Adamson says. —Stephanie Pappas, Scientific American, 24 Apr. 2026

Compass Pathways has been studying a proprietary formulation of synthetic psilocybin for treatment-resistant depression. —Jacqueline Howard, CNN Money, 24 Apr. 2026

The companies are studying psilocybin for treatment-resistant depression and major depressive disorder and methylone for post-traumatic stress disorder (PTSD). —Mary Kekatos, ABC News, 24 Apr. 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)