<p><strong>Noun</strong></p><ul><li>Botany. a usually subterranean and often globular bud having fleshy leaves emergent at the top and a stem reduced to a flat disk, rooting from the underside, as in the onion and lily.</li><li>a plant growing from such a bud.</li><li>any round, enlarged part, especially at the end of a cylindrical object: the bulb of a thermometer.</li><li>Electricity. the glass housing, in which a partial vacuum has been established, that contains the filament of an incandescent electric lamp.</li><li>an incandescent or fluorescent electric lamp.</li><li>Anatomy. any of various small, bulb-shaped structures or protuberances: olfactory bulb; bulb of urethra.</li><li>Building Trades. a rounded thickening at the toe of an angle iron or tee.</li><li>Nautical. a cylindrical or spherical prominence at the forefoot of certain vessels.</li><li>Photography. a shutter setting in which the shutter remains open as long as the shutter release is depressed.</li></ul>