Potable (n.) - Drinking from a toilet...
Drinkable, or safe to drink.
History & Etymology
Potable comes from the PIE root Po- or Poi- which means “to drink.” The suffix -able indicates that it’s possible, or safe. Other words derived from Po(i)- are potion, poison, and symposium. In fact Plato’s dialog “The Symposium” was about the conversation at a drinking party.
The P sound at the beginning of the root is what we call an unvoiced labial plosive. That’s a fancy linguistics word for a sudden release of air from between your lips. But if you change it from unvoiced to voiced by vibrating your vocal chords it becomes a B sound. This is a pretty simple change that happens in languages over time and explains where we got words like beer, beverage, and imbibe.