bulb

noun \ ˈbəlb \

|Updated on: 8 Aug 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

Brava likes to say the bulbs can ramp up to full power in under a second.

— lauren goode, WIRED, "Brava Hopes to Heat Up the 'Smart Kitchen' With a $995 Oven," 10 July 2018
Those cords lead from solar panels in a skylight, carrying energy to light the hanging bulbs.

— charles desmarais, SFChronicle.com, "Charles Desmarais’ art pick for July 15: Susanne Kriemann’s ‘Canopy, canopy’," 7 July 2018
These water-wise bulbs go dormant to survive the long, hot, dry summer.

— nan sterman, latimes.com, "What to do in your garden in July? Less is more," 6 July 2018
Lankenau High School students replaced fluorescent light bulbs in their school with LED lights that use less energy and removed nearly 300 unnecessary fluorescent bulbs.

— michaelle bond, Philly.com, "How can Philly work to solve poverty, climate change, bullying? Teens have answers," 11 Apr. 2018
Next up, stand-up comedian Lewis Black (in Lewis Black fashion) playfully flipped the bird to the flashing bulbs.

— lauren sanchez, Vogue, "The Legendary Robin Williams was Missed and Reminisced at the New York City Premiere for Robin Williams: Come Inside My Mind," 14 July 2018
Remove the stalk and cut the root of the fennel bulb.

— jose cuadros, Philly.com, "Healthy family recipe: Salmon en papillote," 29 June 2018
There will be perennials, flowering bulbs, ground cover, grasses and some small trees and shrubs.

— Courant Community, "Community News For The Manchester Edition," 15 May 2018
Plant potatoes from tubers and onions from sets (small bulbs).

— debbie arrington, sacbee, "Feed your garden so it can feed you | The Sacramento Bee," 23 Feb. 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

See Words from the same year

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