Definition of bolus in English:



  • 1A small rounded mass of a substance, especially of chewed food at the moment of swallowing.

    ‘mucin holds the particles of food together in a ball or bolus’
    • ‘The goal is a reduction in the resting pressure to allow passage of the food bolus into the stomach.’
    • ‘It's a little too raw and undigested at the moment: a massive bolus in my throat.’
    • ‘Peering then through the glass, which demarcated the realms wherein we exist, I felt the bolus of grief form in my gullet.’
    • ‘Once the bolus enters the pharynx, it is transported distally in a structure that can be described as a tubular conduit.’
    • ‘I swallowed the bolus of spittle that was rising in my throat.’
    • ‘The power supply then plugs into that, giving me a very long power cable with a bolus of electrical tape in the middle.’
    • ‘The cardiac sphincter opens because of increasing pressure in the esophagus from the food bolus.’
    • ‘It is important in the lubrication of food boluses, and the amylase in saliva begins the digestion of starches.’
    • ‘Patients may succeed in passing the food bolus by repeated swallowing, by performing the Valsalva maneuver or by making a positional change.’
    • ‘Successively, ingestion, food transport to the processing teeth, chewing and bolus formation, and swallowing can be recognized.’
    • ‘Unfortunately, the bacon lump was much larger than I expected, and as a half-chewed bolus disappeared down my throat, I realised I wouldn't be able to swallow it.’
    • ‘On Midway Island in the Hawaiian chain, a bolus, or mass of chewed food, coughed up by one bird included many identifiable objects.’
    • ‘In preparation for swallowing, a softened or liquid food bolus is moved through the mouth by the action of the tongue.’
    • ‘During summer and autumn, jays routinely make hundreds of food caches per day, placing each saliva-coated bolus in a separate arboreal site.’
    • ‘The program recorded the video as one gigantic bolus, and pretended that the clips were discrete files, which they weren't.’
    • ‘People swallow quite fluid boluses most of the time, and they do so seated with the trunk upright.’
    • ‘After passing the pharynx during swallowing, the food bolus enters the esophagus, which is positioned at approximately the level of the sixth cervical vertebra.’
    • ‘The new thinking is that when you take in a small bolus of protein before exercise, essentially you're giving that protein time to break down while you're working your muscles.’
    • ‘Parent tree swallows deliver food to nestlings in a bolus, making it difficult to determine either the quantity or quality of food.’
    • ‘The tongue directs the bolus of chewed food to the pharynx as an initial step in the involuntary reflex swallowing mechanism.’
    • ‘I said, nonchalantly gulping down a bolus of fear.’
  • 2A type of large pill used in veterinary medicine.

    • ‘Forage intake was estimated at Stillwater using slow-release chromic oxide boluses to estimate fecal output.’
    • ‘This may be due to a large bolus of concentrated solute reaching the myocardium.’
    • ‘All cows with a fever were administered a non-antibiotic regimen of aspirin boluses and probiotic capsules.’
    • ‘Subsequently, the bolus is transferred to the digestive tract where it is chemically reduced.’
    pill, capsule, lozenge, caplet, pastille, pellet, drop, ball
    View synonyms
    1. 2.1Medicine A single dose of a drug or other medicinal preparation given all at once.
      • ‘Treatment was given intravenously as a bolus for the lowest two doses and as a 30-minute infusion for the two highest doses.’
      • ‘Of the eight legs injected with a single 30-ml bolus of dye, seven developed high pressures and one did not.’
      • ‘Some intravenous trials used 1-2 g magnesium sulfate alone, while others used a similar dose as an initial bolus, followed by slower drips over the next few hours.’
      • ‘Upon arrival, he experienced a severe bout of hypotension that was to be treated with a saline bolus.’
      • ‘The drug bolus was followed by continuous infusion of 50 g/kg/hour until the experiment ended at 48 hours.’
      • ‘For an allergic person, a small amount of caffeine acts like a bolus, generating abnormal psychological response, including mania.’
      • ‘The recommended dose for patients with cardiac arrest is 300 mg given intravenously as a bolus.’
      • ‘Typically, local anesthetics and opiates, alone or in combination, are administered through the epidural catheter as an infusion or a bolus to provide analgesia.’
      • ‘Intravenous insulin boluses probably fail because of the short half-life of insulin (ie, approximately five minutes).’
      • ‘The most common error was injecting bolus doses faster than the recommended speed of 3-5 minutes.’
      • ‘We are going to gain venous access and give your baby a fluid bolus because she is shut-down’
      • ‘A low power laser warms the targeted tissue and releases a bolus of photosensitizer.’
      • ‘No data have been reported on the absorption of morphine and other medications added to the fluid bag or given as a bolus.’
      • ‘This has a greater efficacy than a single, large bolus does.’
      • ‘Our analysis shows that the two weak stages in the system are drugs that require multiple step preparation and administration of doses as a bolus.’
      • ‘Trials using high concentration boluses of anaesthetic instead of infusions were excluded.’
      • ‘Although there are few data on nicotine lethality, one report suggests that a bolus of less than I mg/kg is fatal in humans.’
      • ‘An IV bolus of 3-5 g arginine reduced blood pressure and platelet aggregation in patients with type 1 diabetes.’
      • ‘During the night, he became hypotensive, with minimal response to boluses of normal saline.’
      • ‘We found that patients receiving continuous infusions were more deeply sedated than were patients managed with boluses or no sedation, as indicated by both lower SAS scores and lower BIS values.’


Mid 16th century (denoting a large pill): via late Latin from Greek bōlos ‘clod’.