Definition of reflux in US English:



  • 1The process of boiling a liquid in such a way that any vapor is liquefied and returned to the stock.

    • ‘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.’
    • ‘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.’
    • ‘Sugar concentrations in the tips were measured after extraction two times in 4 ml of 80% ethanol boiled with reflux for 20 min.’
    • ‘In general, distillation can be carried out either with or without reflux.’
    1. 1.1technical The flowing back of a liquid, especially that of a fluid in the body.
      • ‘I also had a child with reflux [a kidney infection], which meant she couldn't sleep lying down.’
      • ‘He was also experiencing increased heartburn and obvious gastroesophageal reflux.’
      • ‘Most investigators consider any esophageal pH below 4.0 as the cutoff defining reflux of gastric acid into the esophagus.’
      • ‘I would not have diagnosed reflux on the basis of those records.’
      • ‘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.’


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

    • ‘Second, the alkaloid is refluxed with acetic anhydride for about five hours.’
    • ‘Three liters of 95% ethanol were added to each bottle and then refluxed for 4 hours.’
    • ‘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.’
    • ‘Ginseng root was refluxed with ethanol, and WSF and LSF were prepared from this ethanol extract.’
    1. 1.1technical (of a liquid, especially a bodily fluid) flow back.
      • ‘Normally, this muscle is always contracted, preventing acid from refluxing into the esophagus.’
      • ‘Gastro-oesophageal reflux disease is defined as symptoms or mucosal damage resulting from the exposure of the distal oesophagus to refluxed gastric contents.’
      • ‘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.’
      • ‘If the muscular valve above the stomach leaks, food mixed with acid washes back, or refluxes, into the esophagus.’


Middle English: from re- and flux.