Please concentrate, so does the water! 😊 CONCENTRATE means the water that contains the cumulative amount of substances that were filtered out of the water during reverse osmosis. We will soon be looking at the exact process of reverse osmosis, but today it is enough to know that CONCENTRATE is the waste water from this process, which contains a concentrated amount of substance. By the way, the term itself comes from the French “concentrer” for “to contract” or “unite”, which in turn can be traced back to the Latin “centrum” for “center”.