psilocybin

American  

[sil-uh-sahy-bin, sahy-luh-] / ˌsɪl əˈsaɪ bɪn, ˌsaɪ lə- /

noun

Pharmacology.

1. a hallucinogenic crystalline solid, C 1 2 H 1 7 N 2 O 4 P, obtained from the mushroom Psilocybe mexicana.

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psilocybin British  

/ ˌsaɪlə-, ˌsɪləˈsaɪbɪn /

noun

1. a crystalline phosphate ester that is the active principle of the hallucinogenic fungus Psilocybe mexicana. Formula: C 12 H 17 N 2 O 4 P

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psilocybin Scientific  

/ sĭl′ə-sī′bĭn,sī′lə- /

1. A hallucinogenic compound obtained from certain mushrooms, especially of the genus Psilocybe. Chemical formula: C ₁₂ H ₁₇ N ₂ O ₄ P.

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Etymology

Origin of psilocybin

1955–60; < New Latin Psilocyb ( e ) genus of mushrooms (< Greek psīló ( s ) bare + kýbē head) + -in ²

Example Sentences

See Examples For:

psilocybin

Compass Pathways confirmed an FDA priority voucher for its psilocybin candidate.

From Barron's ● Apr. 24, 2026

Dr. Steven Locke, a former Harvard Medical School psychiatry professor, wrote in an email that the question of whether psilocybin has any medical applications “remains controversial.”

From Los Angeles Times ● Aug. 21, 2025

Dr. Ramaekers adds, "Taken together, averaged and dynamic connectivity analyses suggest that psilocybin alters brain function such that the overall neurobiological pattern becomes functionally more connected, more fluid, and less modular."

From Science Daily ● May 23, 2024

There are few published clinical trials of psilocybin therapy for chronic pain, although many are ongoing, including a pilot study for fibromyalgia conducted by our team at the University of Michigan.

From Salon ● May 13, 2024

But attempts to challenge the patents on Compass’ synthetic psilocybin have been unsuccessful, despite years of work by Turnbull’s patent watchdog group, Freedom to Operate.

From Seattle Times ● Feb. 3, 2024