the violently poisonous seed of an African climbing plant, Physostigma venenosum, of the legume family, the active principle of which is physostigmine.
the dark brown very poisonous seed of a leguminous woody climbing plant, Physostigma venenosum of tropical Africa, used as a source of the drug physostigmine
Calabar bean Cal·a·bar bean (kāl'ə-bär) n. The poisonous seed of a tropical western African woody vine in the pea family and source of the drug physostigmine.