<p><strong>Noun</strong></p><ul><li>Plant Pathology. A disease of rye and other cereal grasses, caused by a fungus of the genus <em>Claviceps</em>, especially <em>C. purpurea</em>, which replaces the affected grain with a long, hard, blackish sclerotial body.</li><li>The sclerotial body itself.</li><li>Pharmacology. The dried sclerotium of <em>C. purpurea</em>, developed on rye plants: used in the production of ergotamine and ergotoxine.</li></ul>