a modified bud consisting of a thickened globular underground stem serving as a reproductive structure
"The gardener carefully unearthed the tulip bulb, revealing its thickened, fleshy base designed to store nutrients and sprout new flowers next spring."
electric lamp consisting of a transparent or translucent glass housing containing a wire filament (usually tungsten) that emits light when heated by electricity
"The old-fashioned bulb in the hallway flickered as its thin wire filament burned out."
anything with a round shape resembling a teardrop
"The delicate glass bulb at the end of her perfume bottle caught the light like a tiny, glowing teardrop."
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"
a rounded dilation or expansion in a canal or vessel or organ
"The surgeon noticed an abnormality as a small bulb within the blood vessel, which was causing a blockage in circulation."
Any solid object rounded at one end and tapering on the other, possibly attached to a larger object at the tapered end.
"The artist crafted several small clay bulbs that tapered down into handles for her new set of cooking utensils."
In plain English: A bulb is an underground plant part that stores food and helps new plants grow from it.
"She bought three new light bulbs to replace the old ones in her bedroom."
Usage: Use this word for any round-tapered object like an onion or light fixture rather than describing something that merely swells in size. When referring to lighting, it specifically denotes the glass enclosure containing the filament or LED source.
To take the shape of a bulb; to swell.
"The onion's skin began to bulge as it absorbed water from the damp soil."
In plain English: To bulb something means to turn it into a light by fitting a lamp inside an existing fixture.
"Don't forget to bulb up your onions before adding them to the soup."
The word "bulb" entered English in the 14th century via Middle English and Old French directly from Latin bulbus. This term originally described a plant characterized by a rounded swelling at its base.