A diseased condition of rye and other cereals, in which the grains become black, and often spur-shaped. It is caused by a parasitic fungus, Claviceps purpurea.
- A fungus (Claviceps purpurea) that infects various cereal plants and forms compact black masses of branching filaments that replace many of the grains of the host plant.
- The disease caused by such a fungus.
- The dried sclerotia of ergot, usually obtained from rye seed and used as a source of several medicinally important alkaloids and as the basic source of lysergic acid.