<p><strong>noun</strong></p><ul><li>any of various fleshy fungi including the toadstools, puffballs, coral fungi, morels, etc.</li><li>any of several edible species, especially of the family Agaricaceae, as <em>Agaricus campestris</em> (meadow mushroom or field mushroom), cultivated for food in the U.S.</li><li>anything of similar shape or correspondingly rapid growth</li><li>a large, mushroom-shaped cloud of smoke or rubble, formed in the atmosphere as a result of an explosion, especially a nuclear explosion</li></ul><p><strong>adjective</strong></p><ul><li>of, consisting of, or containing mushrooms: a mushroom omelet</li><li>resembling a mushroom in shape or form</li><li>of rapid growth and often brief duration: mushroom towns of the gold-rush days</li></ul><p><strong>verb</strong> <em>(used without object)</em></p><ul><li>to spread, grow, or develop quickly</li><li>to gather mushrooms</li><li>to have or assume the shape of a mushroom</li></ul>