castor bean

noun

: the very poisonous seed of the castor-oil plant

also : castor-oil plant

Examples of castor bean in a Sentence

Recent Examples on the Web

Short pod mustard, castor bean, and tree tobacco are shooting up everywhere in the burn scar. — Joy Benedict, CBS News, 4 June 2026

Croton is a relative of castor bean and poinsettia and its milky white sap, like theirs, may irritate the skin. — Joshua Siskin, Oc Register, 14 Feb. 2026

Ricin is a highly toxic chemical that is naturally found in castor beans. — Kirsty Hatcher, PEOPLE, 2 Apr. 2026

Ricin is a natural, highly toxic compound that is a byproduct of processing castor beans. — Sophie Tanno, CNN Money, 17 Apr. 2025

Word History

First Known Use

1819, in the meaning defined above

Rhymes for castor bean

• acridine
• acrolein
• adenine
• alkylene
• aniline
• anthracene
• aquiline
• asphaltene
• atlantean
• atrazine
• butadiene
• butylene

Kids Definition

castor bean

noun

cas·​tor bean

ˈkas-tər-

: the very poisonous seed of the castor-oil plant

also : castor-oil plant

Medical Definition

castor bean

noun

cas·​tor bean ˈkas-tər- 

: the very poisonous seed of the castor-oil plant

also : castor-oil plant