any of a genus (Amanita) of mushrooms (order Agaricales), with white spores and, usually, white gills, some of which, as the death cap and the fly agaric, are very poisonous
Origin:
ModL < Gr amanitai, pl., a kind of fungus
See amanita in American Heritage Dictionary 4
noun
Any of various mushrooms in the genus Amanita, many of which are extremely poisonous.