bulb

Noun

• a rounded dilation or expansion in a canal or vessel or organ

• 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
    

• anything with a round shape resembling a teardrop

• a rounded part of a cylindrical instrument (usually at one end)
  • the bulb of a syringe
    

• electric lamp consisting of a transparent or translucent glass housing containing a wire filament (usually tungsten) that emits light when heated by electricity

• a modified bud consisting of a thickened globular underground stem serving as a reproductive structure

Related words

• Synonyms: 
  medulla oblongata , medulla , light bulb , lightbulb , incandescent lamp , electric light , electric-light bulb