[hir-yuh-din, hir-uh-, hi-rood-n] 
| a gray or white, water-soluble acidic polypeptide obtained from the buccal gland of leeches, used in medicine chiefly as an anticoagulant. |
| hir·u·din (hîr-ōōd'n, hîr'ə-dən, -yə-) n. A substance secreted by the buccal glands of leeches, capable of preventing coagulation by inactivating thrombin and used in medicine as an anticoagulant. [Originally a trademark, from Latin hirūdō, leech.] |
hirudin hir·u·din (hĭ-r&oomacr;d'n, hēr'ə-dən, -yə-)
n.
A substance extracted from the salivary glands of leeches and used as an anticoagulant.