Eau gazifiée: Carbonated water (also known as soda water, sparkling water, fizzy water, club soda, water with gas or (especially in the U.S.) as seltzer or seltzer water) is water containing dissolved carbon dioxide gas, either artificially injected under pressure or occurring due to natural geological processes. Carbonation causes small bubbles to form, giving the water an effervescent quality. Common forms include sparkling natural mineral water, club soda, and commercially-produced sparkling water.