\ ˈbəlb How to pronounce bulb (audio) \
plural bulbs

Definition of bulb

1a : 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

Illustration of bulb

Illustration of bulb

bulb 1a: 1 hyacinth, 2 onion, 3 tulip, 4 lily

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Other Words from bulb

bulbed \ ˈbəlbd How to pronounce bulb (audio) \ adjective
flasks with bulbed necks
bulblike \ ˈbəlb-​ˌlīk How to pronounce bulb (audio) \ or bulb-like adjective
… a large underground rhizome, a bulblike growth that extends massive roots from its underside. — Elizabeth Schneider

Examples of bulb in a Sentence

the bulb of the thermometer
Recent Examples on the Web The lighting is installed recessed so the bulb cannot be seen nor activate skin cancer cells, Knudsen explained. Georgann Yara, The Arizona Republic, 27 May 2021 Coleman's version also has a colorful LED bulb that illuminates while your candle is lit. Kelsey Mulvey, Southern Living, 12 May 2021 The anglerfish is generally known by the luminescent bulb that dangles on a rod atop its head, drawing prey like fish to bait — literally. Los Angeles Times, 10 May 2021 In the seventeenth century, the tulip, native to Turkey, became to the Netherlands what the tomato was to Italy, plus rampant financial speculation: for a brief time, a single bulb cost more than the average Dutchman’s annual salary. Jessi Jezewska Stevens, The New Yorker, 8 May 2021 This will send more energy to the bulb instead of the flower. oregonlive, 1 May 2021 For lamps or light fixtures, make sure to check the bulb. Karen Wytmans, Better Homes & Gardens, 27 Apr. 2021 Your stamped perkins knobs function to light each bulb. Brenda Yenke, cleveland, 1 Apr. 2021 With thin rims that help emphasize the flavor and texture of your wine and a stout bulb-shape glass for maximum breathability, these glasses will actually make your wine taste better — guaranteed. Tim Kohut, BGR, 14 May 2021

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'bulb.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of bulb

15th century, in the meaning defined at sense 1a

History and Etymology for bulb

Middle English, from Latin bulbus, from Greek bolbos bulbous plant

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Time Traveler for bulb

Time Traveler

The first known use of bulb was in the 15th century

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Statistics for bulb

Last Updated

3 Jun 2021

Cite this Entry

“Bulb.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/bulb. Accessed 14 Jun. 2021.

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More Definitions for bulb



English Language Learners Definition of bulb

: a rounded part of some plants that is under the ground and that grows into a new plant during the growing season
: a part that has a rounded shape


\ ˈbəlb How to pronounce bulb (audio) \

Kids Definition of bulb

2 : a dormant stage of a plant that is formed underground and consists of a very short stem with one or more flower buds surrounded by special thick leaves
3 : a plant structure (as a tuber) that is somewhat like a bulb
4 : a rounded object or part the bulb of a thermometer


\ ˈbəlb How to pronounce bulb (audio) \

Medical Definition of bulb

1 : 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

More from Merriam-Webster on bulb

Nglish: Translation of bulb for Spanish Speakers

Britannica English: Translation of bulb for Arabic Speakers

Britannica.com: Encyclopedia article about bulb


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