Potable is an adjective that means ‘suitable for drinking.’ As a noun it refers to ‘a liquid that is suitable for drinking.’
The Latin word potare (poe TAR ay) which means ‘to drink’ is where our word of the day began life. It soon came to be an adjective that meant ‘suitable for drinking’ and a noun that meant a liquid that can be drank.
The biggest problem with many third world countries is the lack of potable water. Being surrounded by water means nothing if the water is not suitable for drinking.