An old-fashioned soda fountain drink made with carbonated water, flavoring syrup and phosphoric acid (H3PO4) for tartness.
Citric acid (C6H8O7)may also be used, or lemon juice in a pinch.
Phosphates come in various fruit flavors, such as cherry, strawberry, lemon, orange, etc.
A lime phosphate may be called a Green River, and a grape one, a Purple Cow.
Phosphates occasionally appear in old movies where the boy and girl drink with two straws out of the same glass while staring dreamily into each other's eyes.
Someone once told me that this is called flurping, but I wouldn't necessarily take my word for it. | 
