noun
1. : any of several plants (as marsh pennywort and butterwort) formerly held to produce rot in sheep
2.
a. : a disease of grapes caused by an imperfect fungus ( Coniothyrium diplodiella ) that produces white or grayish brown-bordered spots on young shoots and fruit
b. : any of several wood rots of various trees caused chiefly by fungi of the genus Fomes
c. : a fungous rot of onions, garlic, shallots, and related plants caused by a fungus ( Sclerotinia cepivorum ) and characterized by production of abundant white mycelium
3. : a watery spoiled condition of eggs in which the white is mixed with the yolk ; also : an egg so spoiled