: the dark brown highly poisonous leguminous seed of a tropical west African woody vine (Physostigma venenosum) that is used as a source of physostigmine and was used formerly as an ordeal poison in African witchcraft trials

Word History

Etymology

Calabar, Nigeria

First Known Use

1853, in the meaning defined above

Time Traveler
The first known use of Calabar bean was in 1853

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Cite this Entry

“Calabar bean.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/Calabar%20bean. Accessed 7 Jul. 2026.

Medical Definition

Calabar bean

noun
: the dark brown poisonous seed of a tropical African woody vine of the genus Physostigma (P. venenosum) that is used as a source of physostigmine

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