bulb Meaning, Definition & Usage

noun a modified bud consisting of a thickened globular underground stem serving as a reproductive structure
noun electric lamp consisting of a transparent or translucent glass housing containing a wire filament (usually tungsten) that emits light when heated by electricity
lightbulb; electric light; light bulb; electric-light bulb; incandescent lamp.
noun a rounded part of a cylindrical instrument (usually at one end)
- the bulb of a syringe
noun anything with a round shape resembling a teardrop
noun lower or hindmost part of the brain; continuous with spinal cord; (`bulb' is an old term for medulla oblongata)
medulla; medulla oblongata.
- the medulla oblongata is the most vital part of the brain because it contains centers controlling breathing and heart functioning
noun a rounded dilation or expansion in a canal or vessel or organ

L. bulbus, Gr. : cf. F. bulbe.

(Bot.) A spheroidal body growing from a plant either above or below the ground (usually below), which is strictly a bud, consisting of a cluster of partially developed leaves, and producing, as it grows, a stem above, and roots below, as in the onion, tulip, etc. It differs from a corm in not being solid.
(Anat.) A name given to some parts that resemble in shape certain bulbous roots; as, the bulb of the aorta.
An expansion or protuberance on a stem or tube, as the bulb of a thermometer, which may be of any form, as spherical, cylindrical, curved, etc. Tomlinson.