Definition of reflux in English:



mass noun
  • 1Chemistry
    The process of boiling a liquid so that any vapour is liquefied and returned to the stock.

    ‘the mixture was heated at reflux under nitrogen’
    • ‘For water extraction of Sophora flavescens, 200 g of dried root was mixed with 1,800 ml of distilled water and extracted under reflux for 3 hr by boiling the mixture.’
    • ‘In general, distillation can be carried out either with or without reflux.’
    • ‘Sugar concentrations in the tips were measured after extraction two times in 4 ml of 80% ethanol boiled with reflux for 20 min.’
    • ‘They looked at various substituted benzaldehydes and cyanoamides and compared the results of traditional ethanol reflux, water reflux and solvent-free conditions.’
    • ‘After separation by TLC and elution from the silica gel, ASG and SG were hydrolysed with 2 N methanolic HCl under reflux for 4 h at 100°C.’
  • 2technical The flowing back of a liquid, especially that of a fluid in the body.

    ‘lying down tends to promote acid reflux’
    as modifier ‘patients with reflux oesophagitis’
    • ‘I also had a child with reflux [a kidney infection], which meant she couldn't sleep lying down.’
    • ‘Most investigators consider any esophageal pH below 4.0 as the cutoff defining reflux of gastric acid into the esophagus.’
    • ‘Just doors away on the same street, Paul Samuels suffered numerous urinary infections and was also diagnosed with the same reflux as the Buckley and Chapman children.’
    • ‘He was also experiencing increased heartburn and obvious gastroesophageal reflux.’
    • ‘I would not have diagnosed reflux on the basis of those records.’


  • 1Chemistry
    no object Boil or cause to boil in circumstances such that the vapour returns to the stock of liquid after condensing.

    no object ‘the liquid is allowed to reflux until the thermometer records the lowest temperature possible’
    with object ‘the solutions were refluxed for 9–12 hours’
    • ‘Three liters of 95% ethanol were added to each bottle and then refluxed for 4 hours.’
    • ‘Ginseng root was refluxed with ethanol, and WSF and LSF were prepared from this ethanol extract.’
    • ‘In the laboratory higher concentration ethanol, with less water, can be produced by refluxing the rectified spirit with quicklime and then distilling the alcohol mixture.’
    • ‘Until 1991, the Defendants manufactured on the site prochloraz-manganese complex; the process involved refluxing prochloraz with manganese chloride, an inorganic compound.’
    • ‘Second, the alkaloid is refluxed with acetic anhydride for about five hours.’
  • 2technical no object, with adverbial of direction (of a liquid, especially a bodily fluid) flow back.

    ‘acidic secretions of the stomach can reflux back upwards’
    • ‘The reflex peristaltic contraction sweeps any refluxed gastric fluid back into the stomach.’
    • ‘The main function of pyloric closure is to reduce the volume of fluid that refluxes into the distal stomach from the duodenum.’
    • ‘Gastro-oesophageal reflux disease is defined as symptoms or mucosal damage resulting from the exposure of the distal oesophagus to refluxed gastric contents.’
    • ‘If the muscular valve above the stomach leaks, food mixed with acid washes back, or refluxes, into the esophagus.’
    • ‘Normally, this muscle is always contracted, preventing acid from refluxing into the esophagus.’


Middle English: from re- and flux.