from
The Collaborative International Dictionary of English v.0.48
Mushroom \Mush"room\, n. [OE. muscheron, OF. mouscheron, F.
mousseron; perhaps fr. mousse moss, of German origin. See
{Moss}.]
1. (Bot.)
(a) An edible fungus ({Agaricus campestris}), having a
white stalk which bears a convex or oven flattish
expanded portion called the pileus. This is whitish
and silky or somewhat scaly above, and bears on the
under side radiating gills which are at first
flesh-colored, but gradually become brown. The plant
grows in rich pastures and is proverbial for rapidity
of growth and shortness of duration. It has a pleasant
smell, and is largely used as food. It is also
cultivated from spawn.
(b) Any large fungus developing a visible fruiting body
with a stem and cap, usu. of the basidiomycetes;
especially one of the genus {Agaricus}; a toadstool.
Several species are edible; but many are very
poisonous. The term mushroom is used most often for
edible varieties, the poisonous ones being termed
{toadstools} or other names. But this distinction is
often ignored.
[1913 Webster +PJC]
2. One who rises suddenly from a low condition in life; an
upstart. --Bacon.
[1913 Webster]