/ Dictionary / Index C citrulline: Meaning and Definition of Find definitions for: cit•rul•line Pronunciation: (si'tru-lēn"), [key] — n. Biochem. an amino acid, NHCONH(CH)CHNHCOOH, abundant in watermelons and an intermediate compound in the urea cycle. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: citrulline (Thesaurus) citron wood citrus Related Content Daily Word Quiz: gregarious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language