Illustration of bulb
- 1 hyacinth
- 2 onion
- 3 tulip
- 4 lily
plural bulbs
1
a
: a resting stage of a plant (such as the lily, onion, hyacinth, or tulip) that is usually formed underground and consists of a short stem base bearing one or more buds enclosed in overlapping membranous or fleshy leaves
b
: a fleshy structure (such as a tuber or corm) resembling a bulb in appearance
c
: a plant having or developing from a bulb
2
: a bulb-shaped part
specifically
: a glass envelope enclosing the light source of an electric lamp or such an envelope together with the light source it encloses
3
: a rounded or swollen anatomical structure
4
: a camera setting that indicates that the shutter can be opened by pressing on the release and closed by ending the pressure
bulblike
adjective
or bulb-like
… a large underground rhizome, a bulblike growth that extends massive roots from its underside.
—
Elizabeth Schneider
Elizabeth Schneider
Examples of bulb in a Sentence
the bulb of the thermometer
Recent Examples on the Web
This is because some types of bulbs and dimmer switches don’t play well together.
—Kamron Sanders, Better Homes & Gardens, 12 July 2025
To access the bulb’s settings, open the app and tap the room where it is installed.
—PC Magazine, 5 July 2025
The blade has a rectangular tip, and the handle ends in a spherical bulb.
—Aspen Pflughoeft
july 4, Miami Herald, 4 July 2025
This foliage is still working making food to strengthen the bulb for the next season.
—Chris McKeown, The Enquirer, 2 July 2025
See All Example Sentences for bulb
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Kamron Sanders, Better Homes & Gardens, 12 July 2025
To access the bulb’s settings, open the app and tap the room where it is installed.
—PC Magazine, 5 July 2025
The blade has a rectangular tip, and the handle ends in a spherical bulb.
—Aspen Pflughoeft
july 4, Miami Herald, 4 July 2025
This foliage is still working making food to strengthen the bulb for the next season.
—Chris McKeown, The Enquirer, 2 July 2025
See All Example Sentences for bulb
Cite this Entry
“Bulb.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/bulb. Accessed 21 Jul. 2025.
Copy CitationKids Definition
bulb
noun1
a
: an underground resting stage of a plant (as an onion or tulip) consisting of a short stem base bearing one or more buds enclosed in overlapping leaves
b
: a fleshy structure (as a tuber or corm) resembling a bulb in appearance or function
2
: a rounded object or part shaped more or less like a bulb
a flashlight bulb
Medical Definition
bulb
noun1
: a rounded dilation or expansion of something cylindrical
the bulb of a thermometer
especially
: a rounded or pear-shaped enlargement on a small base
the bulb of an eyedropper
2
: a rounded part: as
a
: a rounded enlargement of one end of a part see bulb of the penis, bulb of the vestibule, end bulb, hair bulb, olfactory bulb
b
: medulla oblongata
broadly
: the hindbrain exclusive of the cerebellum
c
: a thick-walled muscular enlargement of the pharynx of certain nematode worms
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