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  

/ ˌsɪləˈsaɪbɪn, ˌsaɪlə- /

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

In animals treated with 4e, the compound crossed the blood-brain barrier efficiently and produced a lower but longer lasting level of psilocin in the brain compared with psilocybin.

From Science Daily ● Mar. 8, 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

Fly agarics contain no psilocybin, but two other chemicals: muscimol and ibotenic acid.

From Salon ● Feb. 20, 2025

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