Phosphate soda, also known as an acid phosphate, is a fizzy, acidic beverage that was once a popular thirst-quencher in the United States. Although it is no longer widely available, there are several synonyms for this type of drink. These include an acid drink, soda, carbonated water, or vinegar-based beverage. Acid drink is a term used to describe any drink that contains acidic components, such as lemon or lime juice. Soda and carbonated water both refer to drinks that contain carbon dioxide gas, giving them a fizzy texture similar to phosphate soda. Finally, vinegar-based beverages are another synonym for phosphate soda, as they contain a similar acidic profile.