/ Dictionary / Index H hirudin: Meaning and Definition of Find definitions for: hir•u•din Pronunciation: (hir'yu-din, hir'u-, hi-rd'n), [key] — n. a gray or white, water-soluble acidic polypeptide obtained from the buccal gland of leeches, used in medicine chiefly as an anticoagulant. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. hirtellous Hirudinea Related Content Daily Word Quiz: apogee Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language