low water vs reflux

low water

noun
  • The lowest stage of a river. 

  • The temporary situation of having little money. 

  • The location of low tide in a coastal area. 

reflux

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 boil a liquid in a vessel having a reflux condenser 

  • To flow back or return. 

How often have the words low water and reflux occurred in a corpus of books? (source: Google Ngram Viewer )