bulb meaning and definition

BULB noun

Definition of bulb (noun)

1. a modified bud consisting of a thickened globular underground stem serving as a reproductive structure
2. electric lamp consisting of a transparent or translucent glass housing containing a wire filament (usually tungsten) that emits light when heated by electricity
   • synonyms: electric light, electric-light bulb, incandescent lamp, light bulb, lightbulb
3. a rounded part of a cylindrical instrument (usually at one end)
   • "the bulb of a syringe"
4. anything with a round shape resembling a teardrop
5. 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"
   • synonyms: medulla, medulla oblongata
6. a rounded dilation or expansion in a canal or vessel or organ