- the hard, reddish-brown or black, grainlike masses (sclerotia) of certain parasitic fungi (esp. genus Claviceps) that replace the kernels of rye or other cereal plants
- the disease in which this occurs; specif., the disease of rye caused by a species (Claviceps purpurea) of this fungus
- the dried sclerotia of the rye fungus from which several alkaloids are extracted that have the ability to contract blood vessels and smooth muscle tissue
- any of these alkaloids
Origin of ergot
French from Old French argot, a rooster's spur, hence (from the shape) the disease growth in the plant
