ergot

noun ergots

1. countable, uncountable Any fungus in the genus Claviceps which are parasitic on grasses.
2. countable, uncountable The sclerotium (wintering stage) of certain fungi in the genus Claviceps, appearing as a deformed grain in certain cereals and grasses infected by the fungi. Ergot first appeared on the stage of history in the early Middle Ages, as the cause of outbreaks of mass poisonings affecting thousands of persons at a time. The illness, whose connection with ergot was for a long time obscure, appeared in two characteristic forms, one gangrenous (ergotismus gangrae
3. countable, uncountable The wart-like growth of skin that covers the metacarpal pad on a horse or similar animal. Since the text was in type, Mr. R. I. Pocock has pointed out (The Field, Jan. 20, 1912, p. 143) that the aperture of a scent-gland situated on the posterior aspect of the hind-foot of the Indian rhinoceros occupies a position very nearly similar to that of the ergot in the foot of the horse (infra,