Ergot

Part of speech: noun (n.)

1. 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.

2. The mycelium or spawn of this fungus infecting grains of rye and wheat. It is a powerful remedial agent, and also a dangerous poison, and is used as a means of hastening childbirth, and to arrest bleeding.

3. A stub, like soft horn, about the size of a chestnut, situated behind and below the pastern joint.

4. See 2d Calcar, 3 (b).