bulb
     n 1: a modified bud consisting of a thickened globular
          underground stem serving as a reproductive structure
     2: electric lamp consisting of a glass bulb containing a wire
        filament (usually tungsten) that emits light when heated
        [syn: {light bulb}, {lightbulb}, {incandescent lamp}, {electric
        light}, {electric-light bulb}]
     3: a rounded part of a cylindrical instrument (usually at one
        end); "the bulb of a syringe"
     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" [syn: {medulla oblongata}, {medulla}]
     5: a rounded dilation or expansion in a canal or vessel or
        organ
Source: WordNet® 2.0