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

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

By the end of 2025, however, weed will no longer be permitted as The Coffee Joint seeks to get a psilocybin healing center license and offer opportunities for microdosing mushrooms. —Tiney Ricciardi, Denver Post, 25 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

One of psilocybin’s most promising applications is its role in improving neuroplasticity, the brain’s ability to reorganize itself. —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)