1. any of various fleshy fungi of the class Basidiomycota, characteristically having an umbrella-shaped cap borne on a stalk, especially any of the edible kinds, as those of the genus Agaricus.
2. something shaped like one of these fungi.
3. to multiply, grow, or expand rapidly: the population mushroomed in the postwar decades.
4. to swell or spread out into a shape similar to a mushroom.
5. relating to, consisting of, or containing mushrooms: mushroom sauce.
6. resembling mushrooms in rapidity of growth or evanescence: mushroom towns.

1. any of the fleshy fruiting bodies of fungi typically produced above ground on soil or on their food sources (such as decaying wood).
2. A fungus producing such fruiting bodies.
3. champignon or Agaricus bisporus, the mushroom species most commonly used in cooking.
4. one of the mushroom-shaped pegs in bar billiards.
5. containing or being made of mushrooms.
6. resembling a mushroom by shape or appearance.
7. to grow quickly to a large size.
8. to gather mushrooms.
9. (of a bullet) to form the shape of a mushroom when a bullet impacts a soft target.

1. of or pertaining to mushrooms.
2. resembling mushrooms in rapidity of growth and shortness of duration; short-lived; ephemerial.
3.
4. 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.
5. any large fungus developing a visible fruiting body with a stem and cap, usu. of the basidiomycetes
6. one who rises suddenly from a low condition in life; an upstart.
7. to grow or expand rapidly.
8. to grow so much and so rapidly as to change qualitatively; used with into.

1. A cryptogamic plant of the class fungi: applied in a general sense to almost any of the larger, conspicuous fungi, such as toadstools, puffballs, Hydnei, etc., but more particularly to the agaricoid fungi and especially to the edible forms.
2.
3. an upstart; one who rises rapidly from a low condition in life.
4. A small mushroom-shaped protuberance that sometimes forms on the end of the negative carbon in arc-lamps.
5. of or pertaining to mushrooms; made of mushrooms: as, mushroom sauce.
6. resembling mushrooms in rapidity of growth and in unsubstantiality; ephemeral; upstart: as, mushroom aristocracy.
7. to elevate suddenly in position or rank.
8. having the form or shape of a mushroom or toadstool; formed like the segment of a sphere; said of valves, anchors, etc.
9. to spread out at the top in a form resembling that of a mushroom; curve over at the top; curve down from the top like a mushroom.

1. a large cloud of rubble and dust shaped like a mushroom and rising into the sky after an explosion (especially of a nuclear bomb)
2. fleshy body of any of numerous edible fungi
3. any of various fleshy fungi of the subdivision Basidiomycota consisting of a cap at the end of a stem arising from an underground mycelium
4. pick or gather mushrooms
5. mushrooms and related fleshy fungi (including toadstools, puffballs, morels, coral fungi, etc.)
6. common name for an edible agaric (contrasting with the inedible toadstool)
7. grow and spread fast