bulb

noun \ ˈbəlb \

|Updated on: 13 Jun 2018

Definition of bulb

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

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bulbed

play \ˈbəlbd\ adjective

See bulb defined for English-language learners

See bulb defined for kids

Examples of bulb in a Sentence

the bulb of the thermometer

Recent Examples of bulb from the Web

All park lighting will be energy-efficient LED bulbs.

— laura gómez, azcentral, "Peoria's newest park receives name inspired by surrounding mountains," 6 June 2018
At The Pearl, for example, enjoy an espresso under Edison bulbs inside or linger over a latte by the courtyard in front of Cured.

— mike sutter, San Antonio Express-News, "Top 5 coffee shops in San Antonio," 4 June 2018
Celeriac and Florence fennel bulbs (which are both really stems) may be direct-sown, but are more often started indoors and transplanted.

— pam peirce, SFChronicle.com, "How Bay Area gardeners can grow their own soup," 1 June 2018
The wind howls and low clouds worry the rooftops, but inside the Edison bulbs glow and the wineglasses sparkle and the test kitchen is as snug and clean as a catalog layout.

— ben lowy, Smithsonian, "The Lionfish Have Invaded, But a Ragtag Army of Divers and Chefs Are Fighting Back," 23 May 2018
Jimnalyn Ann Santiago of Plainville added lights to her cap, the tiny bulbs glowing green and blue in a bed of white silk flowers.

— rebecca lurye, courant.com, "Grads Share One More Journey As Blue Devils At CCSU Commencement," 19 May 2018
But the Hue lights do react faster to app commands than most other bulbs, and being able to turn off the lights without having to get up will always be convenient.

— jeff dunn, Ars Technica, "The Ars Technica Mother’s Day gift guide," 7 May 2018
The company is also helping to convert many street lights and other fixtures in government buildings to energy-efficient LED bulbs.

— gregory tejeda, Post-Tribune, "Hammond goes green with new vehicle fleet expected to save $26 million over 15 years," 26 Apr. 2018
Right now, crops near-ready for harvesting include alliums - onions, garlic and garlic scapes (the thin, sometimes curly stalks of hardneck garlic that taste just like the bulb).

— judy walker, NOLA.com, "A guide to New Orleans area produce: When to buy what," 18 Apr. 2018

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.

Illustration of bulb

Origin and Etymology of bulb

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

NEW! Time Traveler

First Known Use: 15th century

in the meaning defined at sense 1a

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BULB Defined for English Language Learners

bulb

noun

Definition of bulb for English Language Learners

: 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

BULB Defined for Kids

bulb

noun \ ˈbəlb \

Definition of bulb for Students

1 : light 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