Dont forget that the etymology of the term "bulb" comes form the formed nature of the glass housing that maintained a non-reactive environment for the filament to glow.
Given their shape, a LED might also be considered a 'bulb', though it operates on a different principle than the incandescant lights that started the term.


(this thread reminds me, did you ever have a discussion online over the proper use of the terms 'drill', 'bit', and 'drill gun'?)