ERGOT

Er″got (?), n. [[F. ergot, argot, lit., a spur.]] 1. 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. 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. 3. (Far.) A stub, like soft horn, about the size of a chestnut, situated behind and below the pastern joint.
4. 4. (Anat.) See 2d Calcar, 3 (b).