/ Dictionary / Index R ricinolein: Meaning and Definition of Find definitions for: ric•in•o•le•in Pronunciation: (ris"u-nō'lē-in), [key] — n. Chem. the glyceride of ricinoleic acid, the chief constituent of castor oil. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. ricinoleic acid ricinus oil Related Content Daily Word Quiz: censure Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language