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

As of 2025, the state’s Natural Medicine Division has begun licensing psilocybin healing centers, which follows Colorado’s recreational legalization of cannabis for people 21 and over in 2014. —John Wenzel, Denver Post, 15 Oct. 2025

Two years ago, Australia legalized prescriptions of MDMA and psilocybin for PTSD and treatment-resistant depression. —Soph Warnes, CNN Money, 28 Sep. 2025

This tour also follows Lorde's two years of MDMA and psilocybin therapy, a PTSD treatment, which helped free her from crippling stage fright. —Audrey Gibbs, Nashville Tennessean, 21 Sep. 2025

In a series of historic moves in 2020, Oregon legalized psilocybin mushrooms for medical use and decriminalized drugs. —Benjamin Adams, Forbes.com, 16 Sep. 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)