Which also gives us rheology (study of flow), diarrhea ("a flowing through"), rhythm (measured flow), etc. Ultimately coming a Proto-Indo-European root (*sreu-?

Which also gives us rheology (study of flow), diarrhea ("a flowing through"), rhythm (measured flow), etc. Ultimately coming a Proto-Indo-European root (*sreu-? I think), which also gives us the Rhine river and the word 'stream', amongst others. The more you know.