reflux

1. the flow of a fluid through a vessel or valve in the body in a direction opposite to normal.

   the majority of leg ulcer patients are elderly with simple superficial vein reflux

   the main culprit is bile reflux, a backup of digestive fluid that is supposed to remain in the small intestine.

2. 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

1. (of a fluid) flow backwards through a vessel or valve in the body.

   acidic secretions of the stomach can reflux back upwards

2. boil or cause to boil in circumstances such that the vapour returns to the stock of liquid after condensing.

   the liquid is allowed to reflux until the thermometer records the lowest temperature possible

   the solutions were refluxed for 9–12 hours

Middle English: from re- and flux.