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

Regulatory tailwinds are strong, with Compass Pathways nearing FDA submission for psilocybin and Definium Therapeutics reporting robust Phase 3 LSD data. — Robert Glatter, Forbes.com, 20 July 2026

Compass has created a psychedelic drug, COMP360, a synthetic form of psilocybin, that earlier this month scored strong Phase 3 results for treating TRD. — Bob Woods, CNBC, 19 July 2026

In depression studies that involved men, psilocybin did not have as great of an impact as other psychedelic medications on oxytocin production. — Camille Hoffman, The Conversation, 7 July 2026

When his oldest son turned 12, Vance admitted to giving his son psilocybin to sell to friends. — Cara Lynn Shultz, PEOPLE, 29 June 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)