WordNet sense 1 (lower or hindmost part of the brain; continuous with spinal cord; (`bulb' is an old term for medulla oblongata)):

medulla, medulla oblongata

WordNet sense 2 (electric lamp consisting of a transparent or translucent glass housing containing a wire filament (usually tungsten) that emits light when heated by electricity):

lightbulb, light bulb, electric light, electric-light bulb, incandescent lamp