(1)   A rounded part of a cylindrical instrument (usually at one end)
"The bulb of a syringe"
(2)   Electric lamp consisting of a transparent or translucent glass housing containing a wire filament (usually tungsten) that emits light when heated by electricity
(3)   A rounded dilation or expansion in a canal or vessel or organ
(4)   Lower or hindmost part of the brain; continuous with spinal cord; (`bulb' is an old term for medulla oblongata)
"The medulla oblongata is the most vital part of the brain because it contains centers controlling breathing and heart functioning"
(5)   A modified bud consisting of a thickened globular underground stem serving as a reproductive structure


  1. Any solid object rounded at one end and tapering on the other, possibly attached to a larger object at the tapered end
  2. A light bulb
  3. The bulb-shaped root portion of a plant such as a tulip, from which the rest of the plant may be regrown.
    • 2005, Plato, Sophist. Translation by Lesley Brown. 265c.
      the plants which grow in the earth from seed or bulbs.

Related terms

  • bulbiferous
  • bulbil
  • bulbous
  • light bulb
  • flash bulb
  • tulip bulb