bulb: Meaning and Definition of

bulb

Pronunciation: (bulb), [key]
— n.
    1. 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.
    2. a plant growing from such a bud.
  1. any round, enlarged part, esp. at the end of a cylindrical object: the bulb of a thermometer.
    1. the glass housing, in which a partial vacuum has been established, that contains the filament of an incandescent electric lamp.
    2. an incandescent or fluorescent electric lamp.
  2. any of various small, bulb-shaped structures or protuberances: olfactory bulb; bulb of urethra.
  3. See
  4. a rounded thickening at the toe of an angle iron or tee.
  5. a cylindrical or spherical prominence at the forefoot of certain vessels.
  6. a shutter setting in which the shutter remains open as long as the shutter release is depressed. Symbol: B
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.
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