/ Dictionary / Index C castor bean: Meaning and Definition of Find definitions for: cas'tor bean" Pronunciation: [key] the seed of the castor-oil plant. See Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Castor and Pollux castoreum Related Content Daily Word Quiz: loathe Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language