Original: Carbonated water , also known as sparkling water , fizzy water , seltzer , and water with gas , ( collectively as an aerated beverage ) , is plain water into which carbon dioxide gas has been dissolved , and is the major and defining component of most soft drinks .
Simplified: Carbonated water , also known as sparkling water , fizzy water , seltzer , and water with gas , is plain water into which carbon dioxide gas has been dissolved .