Emily Dickinson Lexicon

MUSH'ROOM, n. [Fr. mousseron, the white mushroom, from mousse, moss, or the same root, bearing the sense of softness or nap.]

1. The common name of numerous cryptogamian plants of the natural order of Fungi. Some of them are esculent, others poisonous. Mushrooms grow on dunghills and in moist rich ground, and often spring up in a short time. The origin of man, in the view of the atheist, is the same with that of the mushroom. Dwight.
2. An upstart; one that rises suddenly from a low condition in life. Bacon.