Definition of bulb in US English:



  • 1A rounded underground storage organ present in some plants, notably those of the lily family, consisting of a short stem surrounded by fleshy scale leaves or leaf bases, lying dormant over winter.

    Compare with corm, rhizome
    • ‘Glutamyl peptidase activity has been detected in leaves, roots, and bulbs of growing onions, but not in dormant bulbs of variety Southport White Globe.’
    • ‘On the left, a bulb of Fritillaria; bulbs are underground fleshy storage leaves wrapped tightly around the stem, such as in onion and garlic.’
    • ‘Voles have been known to travel tunnels developed by moles to gain access to flower bulbs and other plant roots.’
    • ‘Although they have their favourite plants, they will eat almost anything that's not too tough and leathery including leaves, stems, bulbs, root vegetables, even flowers.’
    • ‘When sold and planted in fall, bulbs are in a dormant state that makes them very easy to handle and ship.’
    • ‘Diet varies with the season but consists primarily of seeds, bulbs, leaves, berries, and some insects.’
    • ‘The buds are already dormant within the bulbs and the difference in size will affect the size of the flower.’
    • ‘Many of their early wildflowers and spring-blooming bulbs go dormant by Memorial Day, so they shrug off the dry summers.’
    • ‘In the chilled bulb, the floral stem is visible in the centre of the bulb, while the leaves and flower have grown outside the sensitive volume of the detection coil.’
    • ‘Snowdrops hate having their roots disturbed, but dividing them in spring allows their roots to recover and gives the leaves time to feed the bulb before they become dormant later in summer.’
    • ‘Treating lily bulbs with cytokinin hormones can mean early flowers and more of them.’
    • ‘If the winters are harsh, then cover the bulbs with straw or leaves.’
    • ‘Not far from West Bank Park, local residents planted daffodil bulbs in the green surround of Holgate Windmill last year.’
    • ‘A wide range of monocots produce bulbs of modified leaves which store food over the winter.’
    • ‘After 12 weeks of storage three of these bulbs were planted to determine the quality of the flowers.’
    • ‘It is a good time to buy and plant conifers and evergreens, summer-flowering bulbs and dahlia tubers.’
    • ‘The fresh weight of roots, bulbs and leaf bases (when the bulbing ratio was < 2) was measured every week or every month.’
    • ‘Checks with Norfolk police revealed that the pair were known to have been involved in the theft of wild flowers, plants and bulbs, which were then re-sold to the public.’
    • ‘No matter what your climate, be sure to water planted bulbs throughout the winter.’
    • ‘Those who received potted lilies can plant the bulbs outside in an area with bright light or in morning sun and afternoon shade.’
    tuber, corm, rhizome
    View synonyms
    1. 1.1 A plant grown from a bulb.
      • ‘Fritillaria bulb is known to contain sixteen different alkaloids that comprise up to 0.4% of the herb by weight.’
      • ‘Transfer the fish to the serving plate on top of the grilled fennel and sprinkle over any reserved fronds/leaves from the fennel bulb.’
      • ‘If there are too many outside layers of skin on the garlic bulbs, pull them off first.’
      • ‘The bulbs should be round, firm and white, with feathery green shoots.’
      • ‘Like its more comely cousin, garlic grows from a bulb, sending a tall green stalk up from the earth to catch sunlight and to flower.’
      • ‘It is also difficult to identify garlics by appearance, since cloves from the same bulb grow differently in different locations.’
      • ‘Each bulb contains a fist full of cloves of varying sizes.’
      • ‘Remove from the heat and strain through a fine mesh sieve, reserving the garlic bulb separately.’
      • ‘Intact garlic bulbs contain alliin, which has no medicinal properties.’
      • ‘So we pumped some flavor in here by adding some of the fennel bulb and some celery, as well.’
      • ‘Add the venison bones, garlic bulb, celeriac, carrots, and bacon and sauté until the bacon fat is rendered, about five minutes.’
      • ‘I also have two small bulbs which are one piece rather than divided into cloves - they grew from bulbils and if replanted will grow into proper divided bulbs next year.’
      • ‘Lachenalias in general are small fleshy bulbs with two upright, opposite leaves.’
      • ‘The most elegant is Tulipa Purissima, pure white and perfectly shaped bulbs tinged with lime green, the ideal spring flower for a formal town garden of clipped bay and box.’
      • ‘Garlic grows in bulbs with even cloves enclosed in a white or pink skin.’
      • ‘They have thin stalks that make braiding easy and the bulbs ' white skins are quite attractive.’
      • ‘The cottage style garden in the Adelaide Hills features a collection of hellebores in a range of colours as well as bulbs and winter flowering shrubs like Magnolia.’
      • ‘Its cloves, of which a bulb contains six to more than two dozen, have little smell when whole but release a notoriously strong one when crushed.’
      • ‘The strong wind may pull the onion leaves down, thus resulting in nutrients being directed toward the onion bulb.’
  • 2A light bulb.

    • ‘Also, that you know the wattage of the bulb and your electric rates.’
    • ‘Turning on a light switch applies a sudden surge to bulbs and transformers, shortening the life of both.’
    • ‘But two days before Friday's grand switch-on ceremony vandals removed bulbs from the display and smashed them in the street.’
    • ‘Compact fluorescents use a third to a quarter of the electricity of standard incandescent bulbs, and last up to 10 times longer.’
    • ‘The reason for this is, if replacement bulbs have a different voltage or wattage to the original set, your lights will be dimmer or brighter and this will overload the light chain and permanently damage the set.’
    • ‘An electrician wired them for low-voltage bulbs and linked them on timers so they go on at dusk.’
    • ‘In December 1878 and February 1879 he demonstrated his first incandescent electric bulbs.’
    • ‘He also added that if someone was smashing thousands of bulbs into a garbage bin then mercury levels in that person's blood would go up.’
    • ‘It was the first to do away with unsightly wires by using the arm structure as an electrical, low voltage conductor to ignite the halogen bulb.’
    • ‘But unlike ordinary incandescent bulbs, they don't have a filament that will burn out, and they don't get especially hot.’
    • ‘Events through the week include a light bulb amnesty at which normal light bulbs can be exchanged for low-energy bulbs donated by Yorkshire Electricity.’
    • ‘When electricity debuted, people did not know what to do with it, other than light a bulb, but this changed once they realized its unlimited potential.’
    • ‘The recycler also reclaims the glass and metal found in the thousands of burned-out bulbs the refinery replaces each year.’
    • ‘The white lights are chosen because of Norwegian tradition (electrical bulbs being the twentieth-century equivalent of candlelight).’
    • ‘In all but the biggest gardens, provided you have reasonably high wattage bulbs and a powerful enough transformer, a simple 12-volt system is enough.’
    • ‘I want to be able to buy Thai spices in the market town and I want my local electrical shop to sell 500 different types of low-voltage bulbs.’
    • ‘If the illumination source does not include a spectrum close to that of incandescent bulbs or the sun, then the color of objects will be different than what we are accustomed to.’
    • ‘In the days when all traffic lights consisted of incandescent bulbs behind a plastic filter, the heat produced by the lamps was not much of an issue for designers.’
    • ‘Thus argon is used to fill tungsten filament bulbs and fluorescent tubes: no matter how hot the filament gets, argon will not react with it.’
    • ‘The church was lit by half-a-dozen electric bulbs (arranged in two rows of three like the dots on a six-point domino).’
  • 3An expanded part of a glass tube such as that forming the reservoir of a thermometer.

    • ‘It was a narrow glass tube with a bulb at the bottom.’
    • ‘Another gadget, a simple glass bulb with four small vanes inside, the faces of each painted black or white.’
    • ‘The grains of sand teeter on the edge of the glass bulb.’
    • ‘Crookes's tube consisted of a glass bulb, from which most of the air had been removed, encasing two metal plates called electrodes.’
    • ‘The instrument, consists of two glass bulbs united by a narrow neck.’
    • ‘They consisted of a curved U-tube filled with mercury attached to a bulb containing creosote.’
    • ‘Yesterday, all the bulbs in my galileo thermometer were up the top.’
    • ‘The result is an hourglass shaped vessel, with both the upper and lower bulbs holding 2 oz.’
    • ‘A wet bulb thermometer is simply a thermometer with the bulb wrapped in moist muslin.’
    • ‘A glass bulb, then, is used to keep oxygen away from the filament.’
    1. 3.1 A hollow flexible container with an opening through which the air can be expelled by squeezing, such as that used to fill a syringe.
      • ‘You would get less mercury in the dropper than you would water if you squeezed the bulb equally in both cases.’
      • ‘Release pressure (let the air back in) on the bulb until the nose is clear.’
      • ‘Release the bulb, holding it in place while it suctions the mucus from your baby's nose.’
      • ‘Gently put the compressed bulb into the open nostril.’
      • ‘The third time I arranged things just so, manoeuvred the syringe into my ear, reaching over the top of my head with my left hand, and squeezed the tiny rubber bulb gently.’
      • ‘Gently suction out the nose with an ear bulb every few hours.’
      • ‘Empty the contents onto a tissue by squeezing the bulb rapidly while holding it upside down.’
      • ‘Nicola took out a small medicine bottle with a bulb syringe, and began with delicate squeezes of the bulb to collect the moisture that gathered at the corners of the child's eyes.’
      • ‘Blow out the dust with compressed air, canned air, a blow-out bulb (ear syringe), or a vacuum in the blower mode.’
      • ‘Using a bulb syringe and saline nose drops can also help to keep a baby's nose clear.’
      • ‘Air cast pressure was changed by manually increasing air volume with a BP bulb; pressure was continuously monitored with a mercury manometer.’
      • ‘Dry the syringe bulb and store it in a cup or container.’
      • ‘Multiple delivery methods and devices have been studied but not compared, including bottles or pots, bulb syringes, inhalers, and nebulizers.’
      • ‘Droppers with rubber bulbs should not be kept with the essential oil bottle as the highly concentrated oil can turn the rubber bulb into gum.’
      • ‘A bulb syringe to be used to remove mucous from the mouth/nose’
      • ‘Labels that do not adhere adequately to the bulb syringe could increase the risks of leaving foreign bodies in the surgical wound.’
      • ‘If your baby is having trouble sucking, try using a rubber suction bulb to help clear his or her nose before each feeding.’
      • ‘The scrub person drapes the infant warmer with sterile terry cloth towels and ensures that there are two bulb syringes and cord clamps in the warmer.’
      • ‘The infant developed mild respiratory distress at delivery that resolved with bulb and orogastric suction and administration of free-flow oxygen.’
      • ‘Use a suction bulb or put some of the warm salt water in the cup of your hand to sniff it up one nostril at a time.’
    2. 3.2 A spheroidal dilated part at the end of an anatomical structure.
      • ‘An upper gastrointestinal tract endoscopy showed mucosal telangiectasia in the stomach and duodenal bulb.’
      • ‘A skin biopsy from one of the patches found many empty hair bulbs without any inflammation or scarring.’
      • ‘If it is exactly in the midline, it may be the duodenal bulb, the pylorus, or the distal antrum.’
      • ‘Muscular sphincters may exist anteriorly or posteriorly in the pharyngeal bulb.’
      • ‘For the sense of smell, odors are processed in an area of the brain called the olfactory bulb.’
      • ‘These neuroendocrine tumors arise from the adventitia of the jugular bulb or the neural plexus within the middle ear space.’
      • ‘The middle-right arrow shows tissue similar to the uterus and ejaculatory bulb cortex.’
      • ‘When light reaches your hair follicles, it temporarily generates enough heat to destroy the follicles and bulbs.’
      • ‘Venous hums may be heard in patients with hypertension or abnormally high placement of the jugular bulb.’
      • ‘Similar tumors may arise from neighboring areas, including the jugular bulb, the middle ear, and the mastoid portion of the temporal bone.’
      • ‘He observed long processes of sensory neurons coursing into the brain from the retina and olfactory bulb.’
      • ‘The offactory bulb in the nose and the pleasure center of the brain are connected by a direct sensory pathway.’
      • ‘Loss of gar - 3 function speeds up the repolarization of the terminal bulb muscles and shortens action potentials.’
      • ‘An anomalous carotid artery or jugular bulb may present in a similar fashion.’
      • ‘Loss of gar - 3 function results in shortened action potentials and brief muscle contractions in the pharyngeal terminal bulb.’
      • ‘We report a case of Brunner gland hamartoma of the duodenal bulb with unusual histologic features.’
      • ‘The lower esophagus and duodenal bulb are common sites of gastric metaplasias occurring as a protective response to the injurious action of gastric acid.’
      • ‘Everything from the beginning of the esophagus to the posterior of the anterior bulb was considered ‘foregut.’’
      • ‘Glomus tumor is a vascular neoplasm arising from the paraganglia around the carotid bifurcation, the jugular bulb, or the tympanic arteries.’
      • ‘An additional set of 10, usually monociliary gland cells opens anteriorly and outside of the pharyngeal bulb into the mouth cone lumen.’


Late Middle English: via Latin from Greek bolbos ‘onion, bulbous root’.