bulb

noun \ ˈbəlb \

Updated on: 19 Apr 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

Thinly slice one bulb of fennel and sauté it in that sausage fat until tender; season with a little salt.

— alex delany, Bon Appetit, "This Tax Season Stromboli Recipe Is My Only Dependent," 9 Apr. 2018
And then, amid a cacophony of firing flash bulbs and video camera operators fighting one another for position, the biggest celebrity of the NCAA tournament rolled in.

— andy staples, SI.com, "Sister Jean is Embracing Her Role as the Face of Loyola-Chicago, NCAA Tournament," 30 Mar. 2018
Instead Hollinghurst uses that opening section as an origin point, like a dry little bulb that will later sprout tulips of consequence.

— josephine livingstone, The New Republic, "Alan Hollinghurst’s Long Journey," 30 Mar. 2018
And that year, the first string of Christmas lights, 16 bulbs, went up on the Suydam Building.

— darryl levings, kansascity, "From swampy to swanky, the Country Club Plaza is born | The Kansas City Star," 23 Mar. 2018
Softnecks get their name because the whole green plant dies down, leaving nothing but the bulb and flexible stems that are easy to braid.

— leslie land, Good Housekeeping, "How to Grow Garlic," 21 Mar. 2018
That book was the blueprint for many joyful birthdays, where happiness was found at the end of a 60-watt light bulb screwed into my Susie Homemaker oven.

— christine m. flowers, Philly.com, "RIP Toys R US: Remembering brand new Barbies and green plastic soldiers in the age of e-commerce | Christine Flowers," 15 Mar. 2018
Jackson Sumner also boasts a 26-foot-tall waterfall that puts ions into the air and uses lights with softer hues than a standard fluorescent bulb.

— rebecca greenfield, latimes.com, "Why your office is beginning to look like a forest," 9 Feb. 2018
Look for a smooth, firm, pale-ivory (rather than brown) bulb that smells fresh and clean.

— Sunset, "Asian Market Shopping Guide," 22 Jan. 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

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First Known Use: 15th century

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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