: 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
… a large underground rhizome, a bulblike growth that extends massive roots from its underside. —Elizabeth Schneider
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
Examples are automatically compiled from online sources to
show current usage.Read More
Opinions expressed in the examples do not represent those of Merriam-Webster or its editors.
Send us feedback.
This includes simple measures like measuring wet-bulb globe temperatures—as read by a thermometer covered in a damp cloth to measure relative humidity—on their production floors.—Jasmin Malik Chua, Sourcing Journal, 25 Sep. 2025 Fall is the best time to plant spring-flowering bulbs and native plant seeds that benefit from cold stratification, like milkweed and bee balm.—Lauren Landers, Better Homes & Gardens, 25 Sep. 2025 Just remember to pull leaves back in early spring to give bulbs and perennials room to grow.—Brendel Clark, Freep.com, 25 Sep. 2025 Rodents may dig up the tubers, so plant them in bulb baskets underground or in DIY cages made from chicken wire.—Arricca Elin Sansone, Southern Living, 24 Sep. 2025 See All Example Sentences for bulb
Word History
Etymology
Middle English, from Latin bulbus, from Greek bolbos bulbous plant
: 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
Share