Reflux
/ˈɹiː.flʌks/
noun
The backwards flow of any fluid.
A technique, using a reflux condenser, allowing one to boil the contents of a vessel over an extended period.
The leaking of stomach acid up into the oesophagus.
verb
To flow back or return.
“the refluxing tide”
To boil a liquid in a vessel having a reflux condenser