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
bulbed adjective
flasks with bulbed necks
bulblike adjective
or bulb-like
… a large underground rhizome, a bulblike growth that extends massive roots from its underside. Elizabeth Schneider

Illustration of bulb

Illustration of bulb
  • 1 hyacinth
  • 2 onion
  • 3 tulip
  • 4 lily

Examples of bulb in a Sentence

the bulb of the thermometer
Recent Examples on the Web The book is about flower bulb grower Luther Gage, who cultivated the giant Tecolote ranunculus, which can be seen at The Flower Fields in Carlsbad. Linda McIntosh, San Diego Union-Tribune, 2 Mar. 2024 Best Buy is discounting a Philips Hue starter kit containing three color A19 bulbs, a Hue Bridge, and a wall-mountable dimmer switch for $119.99 ($50 off). Quentyn Kennemer, The Verge, 1 Mar. 2024 Fresh fennel looks a little bit like celery’s cooler cousin, with its layered bulb, protruding stalks and frilly fronds. Aaron Hutcherson, Washington Post, 27 Feb. 2024 While the bulbs must be planted in fall, nowadays sprouting daffodils can be found in garden centers to plant in spring. Southern Living Editors, Southern Living, 14 Feb. 2024 However, the bulbs give off insufficient light for true illumination. Alida Nugent, Better Homes & Gardens, 14 Feb. 2024 His go-to for table lamps is the Schoolhouse Matte Porcelain LED bulb. Caitie Kelly Gisela Williams Julekha Dash Catherine Hong Devorah Lev-Tov, New York Times, 15 Feb. 2024 The bulbs can also be adjusted to either warm or cool lighting. Alida Nugent, Better Homes & Gardens, 14 Feb. 2024 Ultraviolet Lamps and Bulbs People at high risk of vitamin D deficiency may resort to UV-emitting lamps and bulbs. Ella Quittner, Health, 9 Feb. 2024

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'bulb.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

Etymology

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

First Known Use

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

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

Dictionary Entries Near bulb

Cite this Entry

“Bulb.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/bulb. Accessed 19 Mar. 2024.

Kids Definition

bulb

noun
1
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

noun
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

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