ergot (n.) Look up ergot at Dictionary.com
fungal disease of rye and other grasses, 1680s, from French ergot, from Old French argot "cock's spur" (12c.), of unknown origin. The blight so called from the shape the fungus forms on the diseased grain. Ergotism "disease caused by eating ergot-infected breadstuffs," first recorded 1853. An alkaloid from the fungus, ergotamine (1921) is used to treat migraines.